129 Evolution News Articles
for August 2016
Click on the links below to get the full story from its source
8-31-16 In drought, zebra finches wring water from their own fat
In drought, zebra finches wring water from their own fat
Deprived birds shown to rely less on stored proteins to quench thirst. Thirsty zebra finches “drink” their body fat. The songbirds are the first birds shown to get through a day without water by breaking down adipose tissue to stay hydrated, says evolutionary physiologist Ulf Bauchinger. Two earlier tests of deprived birds summoning water from their tissues report that birds rely on protein. But zebra finches (Taeniopygia guttata) coped with one-day droughts in the lab not by breaking down such tissues as muscle but with the safer choice of metabolizing fat, say Bauchinger, Joanna Rutkowska and their colleagues at Jagiellonian University in Kraków, Poland. In comfortable temperatures and humidity, the little birds (averaging 13.5 grams in weight) produced about 0.444 grams of water metabolically. That boost would have taken large amounts of fleshy moist protein, equivalent to one-third the mass of their flight muscles or three times the mass of their hearts, the researchers say online August 31 in the Journal of Experimental Biology.
8-31-16 Mind-controlled nanobots could release drugs inside your brain
Mind-controlled nanobots could release drugs inside your brain
NOW that’s a powerful thought. For the first time, a man has controlled nanorobots inside a living creature just by doing mental calculations. The technology released a drug inside cockroaches in response to the man’s brain activity. It was designed by a team at the Interdisciplinary Center in Herzliya and Bar Ilan University in Ramat Gan, both in Israel, to allow precise control over when a drug is active in the body, reducing side effects. These nanobots are built out of DNA, forming shell-like shapes that drugs can be tethered to. They have a gate with a lock made from iron oxide nanoparticles that can be opened when heated with electromagnetic energy. Because the drug is tethered to the DNA parcel, opening and closing the gate controls how much drug the body is exposed to. To get the DNA bots to respond to a person’s thoughts, the team trained a computer algorithm to distinguish between a person’s brain activity when resting and when doing mental arithmetic. Next, the group attached a fluorescent drug to the bots and injected them into a cockroach sitting inside an electromagnetic coil. A man wearing an EEG cap that measures brain activity triggered exposure to these fluorescent drugs simply by doing calculations in his head (PLoS, doi.org/bpwp).
8-31-16 Wavy Greenland rock features 'are oldest fossils'
Wavy Greenland rock features 'are oldest fossils'
Some of the world’s earliest life forms may have been captured in squiggles found in ancient rocks from Greenland. The rocks were part of the seafloor 3.7 billion years ago, and the wavy lines, just a few centimetres across, would be remnants of primordial microbial colonies called stromatolites. The evidence is presented in the academic journal Nature. If confirmed, the colonies would predate the previously oldest known fossils by over 200 million years. To put that in context, travelling back a similar time from today would be to leap into the world of the first dinosaurs. But all claims of extremely early life are hotly contested, and this find is as well.
8-31-16 Ancient rock formations could be oldest fossils on the plane
Ancient rock formations could be oldest fossils on the plane
Rocks in Greenland that have been preserved for 3.7 billion years show evidence of microbes living in a shallow sea on early Earth. They could be the earliest fossils ever found. Structures discovered in 3.7-billion-year-old rocks in Greenland appear to be evidence of microbes living in a shallow sea on early Earth. The structures, all no more than a few centimetres tall, look like stromatolites. These are layered mounds that were – and still are – formed by photosynthetic microbes living in water. The fossils’ age makes them about 220 million years older than any previous fossil found. They come from a region of south-west Greenland called the Isua supracrustal belt. “This is one of the extremely few places where this kind of feature could still be preserved in the rock record,” says Allen Nutman at the University of Wollongong in Australia, who led the team.
8-31-16 Greenland may be home to Earth’s oldest fossils
Greenland may be home to Earth’s oldest fossils
3.7-billion-year old mounds signal early microbes. The wavelike mounds of sediment called stromatolites embedded inside a cross section of a 3.7-billion-year-old rock may be the oldest known fossilized evidence of life on Earth. A melting snow patch in Greenland has revealed what could be the oldest fossilized evidence of life on Earth. The 3.7-billion-year-old structures may help scientists retrace the rise of the first organisms relatively soon after Earth’s formation around 4.5 billion years ago (SN: 2/8/14, p. 16), the discoverers report online August 31 in Nature. Unlike dinosaur bones, the new fossils are not preserved bits of an ancient critter. The Greenland fossils are mounds of minerals a few centimeters tall that may have been deposited by clusters of microbes several hundred million years after Earth formed. The shape and chemical composition of the mounds, called stromatolites, match those formed by modern bacterial communities living in shallow seawater, says a team led by geologist Allen Nutman of the University of Wollongong in Australia.
8-31-16 Why forgetting is actually good for you
Why forgetting is actually good for you
Stop trying to improve your memory. You don't need to remember everything. But, alongside the studies telling us how to keep our memories intact, an enormous body of research has led to another conclusion: In many cases, it's okay (and in fact, beneficial) to forget. Human memory is not only unreliable, but often partially or wholly false. And certain kinds of forgetting is actually really good for us. Every time we retrieve a memory, the brain delivers a partial picture, one that's less like a computer document and more like a slice of Swiss cheese. Those cheesy holes get filled in with information that may or may not be true. Then, when we are finished with the new version of the memory, the brain consolidates and "repacks" it, losing some facts and keeping some of that sketchy filler that's part truth and part fabrication. The more times we retrieve and recount a memory, the less trustworthy it becomes.
8-31-16 Elephants' footprints leave behind tiny oases for aquatic life
Elephants' footprints leave behind tiny oases for aquatic life
In a Ugandan swamp forest, ponds formed by the stomping of elephants are quickly inhabited by dozens of species. That’s one small step for an elephant, but a giant leap for the survival of tiny aquatic animals. In the swamp forests of Kibale National Park, Uganda, every step elephants take can give rise to a footprint-shaped mini-pond, holding up to 200 litres of water and dozens of invertebrate species. “I was surprised to find out that these footprints were water-filled all year round, and that they harboured such a high diversity,” says Wolfram Remmers at the University of Koblenz in Germany. Surveying 30 such prints over a three-day period in 2014, Remmers and his colleagues found over 60 species, including beetles, spiders and worms – plus tadpoles. Many smaller species may live there, too – the team’s sampling method meant they only caught things bigger than 2 millimetres. The footprints probably play an important role in allowing these small life forms to spread, as they form a network of connected ponds.
8-31-16 Tail vibrations may have preceded evolution of rattlesnake rattle
Tail vibrations may have preceded evolution of rattlesnake rattle
The rattlesnake rattle evolved only once. A new study contends that it may have evolved out of a simple behavior, tail vibration, that is common among many snake species. Even if you’ve never lived in rattlesnake territory, you know what the sound of a snake’s rattle means: Beware! A shake of its rattle is an effective way for a snake to communicate to a potential predator that an attack could result in a venomous bite. For more than a century, scientists have posited how that rattle might have evolved. The rattle is composed of segments of keratin (the same stuff that makes up human hair), and specialized muscles in a snake’s tail vibrate those segments rapidly to create the rattling sound. The rattlesnake’s rattle is a trait that evolved only once in the past and is now found in only two closely related genera of snakes that live in North and South America. But plenty of other species of snakes also vibrate their tails as a warning to potential predators.
8-30-16 Brain’s blood appetite grew faster than its size
Brain’s blood appetite grew faster than its size
Evolution of hominid mental abilities demanded more fuel, study finds. The internal carotid arteries pass into the skull through two tiny holes. Scientists measured these openings in hominid fossils to estimate changes in blood flow rates to the brain across human evolution. The brains of human ancestors didn’t just grow bigger over evolutionary time. They also amped up their metabolism, demanding more energy for a given volume, a new study suggests. Those increased energy demands might reflect changes in brain structure and organization as cognitive abilities increased, says physiologist Roger Seymour of the University of Adelaide in Australia, a coauthor of the report, published online August 31 in Royal Society Open Science.
8-30-16 Tasmanian devil DNA shows signs of cancer fightback
Tasmanian devil DNA shows signs of cancer fightback
A genetic study of Tasmanian devils has uncovered signs that the animals are rapidly evolving to defend themselves against an infectious face cancer. One of just three known transmissible cancers, this tumour has wiped out 80% of wild devils in the past 20 years. Researchers looked at samples from 294 animals, in three different areas, before and after the disease arrived. Two small sections of the devil genome appear to be changing very fast - and contain likely cancer-fighting genes.
8-30-16 Tasmanian devils evolve resistance to contagious cancer
Tasmanian devils evolve resistance to contagious cancer
Genetic tweaks helping threatened marsupials beat deadly tumors. Some genetic variants may have allowed a small number of Tasmanian devils to withstand a deadly contagious facial tumor that has killed up to 95 percent of them in some locales. The discovery could be good news for the species. A few Tasmanian devils have started a resistance movement against a contagious cancer that has depleted their numbers. Since devil facial tumor disease was first discovered in 1996, it has wiped out about 80 percent of the Tasmanian devil population. In some places, up to 95 percent of devils (Sarcophilus harrisii) have succumbed to facial tumors, spread when devils bite each other. Scientists had believed the tumor to be universally fatal. But a new study finds that a small number of devils carry genetic variants that help them survive the disease — at least long enough to reproduce, researchers report August 30 in Nature Communications. The finding could be important for the survival of the species.
8-30-16 DNA sequenced in space for first time
DNA sequenced in space for first time
DNA has been successfully sequenced in space for the first time. Nasa astronaut Kate Rubins carried out the test on the International Space Station (ISS) at the weekend. She was using a compact DNA sequencing device called Minion, which was developed in the UK. The device, which was sent up to the space station in July, could help astronauts diagnose illness in space and allow them to identify disease-causing microbes on the ISS. DNA sequencing is the process used to determine the order of the four chemical building blocks that make up the genetic information from a given living organism.
8-30-16 Geologists search for Anthropocene 'golden spike'
Geologists search for Anthropocene 'golden spike'
The notion that we have entered a new geological age is real and should be formally recognised, according to an international report. The verdict comes from a panel set up to judge the merits of adding an Anthropocene ("Age of Humans") time segment to the history of the Earth. The group delivered its preliminary evidence and recommendations on Monday. It now needs to identify a suitable marker in the environment that epitomises the start of the new phase.
8-30-16 Early human ancestor Lucy 'died falling out of a tree'
Early human ancestor Lucy 'died falling out of a tree'
New evidence suggests that the famous fossilised human ancestor dubbed "Lucy" by scientists died falling from a great height - probably out of a tree. CT scans have shown injuries to her bones similar to those suffered by modern humans in similar falls. The 3.2 million-year-old hominin was found on a treed flood plain, making a branch her most likely final perch. It bolsters the view that her species - Australopithecus afarensis - spent at least some of its life in the trees.
8-29-16 Fossil autopsy claims Lucy fell from tree
Fossil autopsy claims Lucy fell from tree
Disputed analysis says early hominid broke multiple bones. Scientists say that damage to the 3.2-million-year-old partial skeleton dubbed Lucy suggests that this ancient hominid plummeted to her death from high in a tree. That’s a controversial conclusion. In a macabre twist, the hominid evolutionary tree’s most famous fossil star, Lucy, tumbled to her death from high up in a tree, a controversial new study suggests. Some of the damage to Lucy’s 3.2-million-year-old partial skeleton most likely occurred when she fell from a height of 13 meters or more, say paleoanthropologist John Kappelman of the University of Texas at Austin and his colleagues. Lucy, an ancient ambassador of a prehuman species called Australopithecus afarensis, must have accidentally plunged from a tree while climbing or sleeping, the scientists propose online August 29 in Nature.
8-29-16 GluMI cells are anything but
GluMI cells are anything but
In the retina, newly identified nerve cells inspire action. A GLuMI nerve cell is tucked among bipolar nerve cells with two arms , photoreceptors and ganglion cells in a mouse retina. Despite its name, the newly identified GluMI cell (pronounced “gloomy”) is no downer. It’s a nerve cell, spied in a mouse retina, that looks like one type of cell but behaves like another. Like neighboring retina nerve cells that subdue, or deaden, activity of other nerve cells, GluMI cells have a single arm extending from their body. But unlike those cells, GluMI cells actually seem to ramp up activity of nearby cells in a way that could aid vision. GLuMIs don’t seem to detect light firsthand, but they respond to it, Luca Della Santina of the University of Washington in Seattle and colleagues found. GluMIs are among a growing list of unexpected and mysterious cells found in the retinas of vertebrates, the researchers write August 8 in Current Biology.
8-27-16 How ancient solar storms etched 'secret clocks' in tree rings
How ancient solar storms etched 'secret clocks' in tree rings
Astronomers and archaeologists seldom work alongside one another — when scientists study the stars they're exploring the future, while ancient potsherds are firmly grounded in the past. But a recent study in the Royal Society Journal Proceedings describes a mathematical method that could help archeologists date ancient events and civilizations down to the precise year. And its key ingredient? Solar flares. Researchers found that intense solar flares in the years 775 and 994 AD caused spikes in atmospheric carbon around the world, leaving their traces in tree rings, reeds, and papyri. Under the right conditions — and with little mathematical elbow grease — these radiocarbon spikes can be used as time-markers, which the authors call "secret clocks," hidden in organic material. "In the past, we have had floating estimates of when things may have happened," said coauthor Michael Dee of the University of Oxford, in a press statement. "But these secret clocks could reset chronologies concerning important world civilizations with the potential to date events that happened many thousands of years ago to the exact year."
8-26-16 Sex reshapes the immune system to boost chances of pregnancy
Sex reshapes the immune system to boost chances of pregnancy
As well as fertilising the egg, semen seems to dampen a female's immune system, making it more likely that an embryo will survive. Semen does more than fertilise eggs. In mice, it seems to prime the female’s immune system for pregnancy, making it more likely that an embryo will successfully implant in the womb. It appears to prompt similar changes in women, a finding that could explain why IVF is more successful in during treatment. Sarah Robertson at the University of Adelaide, Australia, and her colleagues found that each time a female mouse copulates, it caused the release of immune cells called regulatory T-cells, which are known to dampen down inflammation in the body. This process may be important for allowing embryos to implant in the womb, rather than being rejected as a foreign body. In people, low regulatory T-cell counts are linked to several reproductive problems, including unexplained infertility, miscarriage, pre-eclampsia and pre-term labour.
8-25-16 Lyme bacteria swap ‘catch bonds’ to navigate blood vessels
Lyme bacteria swap ‘catch bonds’ to navigate blood vessels
Infection spreads via technique also used by immune system’s white blood cells. To zip through the bloodstream and spread infection throughout the body, the bacteria that cause Lyme disease take a cue from the white blood cells trying to attack them. Both use specialized bonds to stick to the cells lining blood vessels and move along at their own pace, biologist Tara Moriarty and colleagues report September 6 in Cell Reports. “It’s really an amazing case of convergent evolution,” says Wendy Thomas, a biologist at the University of Washington in Seattle who wasn’t part of the study. “There’s little structural similarity between the molecules involved in these behaviors, and yet their behavior is the same.”
8-25-16 Cool nerve cells help mice beat heat
Cool nerve cells help mice beat heat
Scientists identify sensors in part of hypothalamus key to regulating body temperature. Scientists have identified the “refrigerator” nerve cells that hum along in the brains of mice and keep the body cool. These cells kick on to drastically cool mice’s bodies and may prevent high fevers, scientists report online August 25 in Science. The results “are totally new and very important,” says physiologist Andrej Romanovsky of the Barrow Neurological Institute in Phoenix. "The implications are far-reaching." By illuminating how bodies stay at the right temperature, the discovery may offer insights into the relationship between body temperature and metabolism.
8-25-16 Genes help snub-nosed monkeys live the high life
Genes help snub-nosed monkeys live the high life
A few genes may have put black snub-nosed monkeys on top of the world. Black, or Yunnan, snub-nosed monkeys (Rhinopithecus bieti) live in high-altitude forests on a small slice of the Tibetan plateau. At 3,400 to 4,600 meters above sea level, the monkeys reside at higher elevations than any other nonhuman primate. A genetic study of DNA from four of the five remaining species of snub-nosed monkeys in Asia has found 19 gene variations in black snub-nosed monkeys that might be responsible for their high life. One of those genes, called ADAM9, is more active in cancer cells in low-oxygen conditions. Tibetan yaks and chickens also have their own versions of the gene. The results suggest that natural selection favored changes to ADAM9 because they help snub-nosed monkeys and other animals survive low-oxygen environments.
8-25-16 Mind-controlled nanobots could release drugs inside your brain
Mind-controlled nanobots could release drugs inside your brain
DNA origami bots have been triggered to release drugs inside cockroaches, prompted by changes in a person’s brain activity. A man has used thought alone to control nanorobots inside a living creature for the first time. The technology released a drug inside cockroaches in response to the man’s brain activity – a technique that may be useful for treating brain disorders such as schizophrenia and ADHD. Getting drugs to where they need to be exactly when you want them is a challenge. Most drugs diffuse through the blood stream over time – and you’re stuck with the side effects until the drug wears off. Now, a team at the Interdisciplinary Center, in Herzliya, and Bar Ilan University, in Ramat Gan, both in Israel, have developed a system that allows precise control over when a drug is active in the body. The group has built nanorobots out of DNA, forming shell-like shapes that drugs can be tethered to. The bots also have a gate, which has a lock made from iron oxide nanoparticles. The lock opens when heated using electromagnetic energy, exposing the drug to the environment. Because the drug remains tethered to the DNA parcel, a body’s exposure to the drug can be controlled by closing and opening the gate.
8-25-16 Thank (or blame) your genes for ability to handle java jolt
Thank (or blame) your genes for ability to handle java jolt
New genetic link to caffeine metabolism found. A study of Italian and Dutch people’s DNA revealed a new gene that may affect how much coffee people drink. The gene is involved in determining how well people process caffeine. Coffee consumption may be in the genes. Activity of a gene that lowers levels of caffeine-degrading enzymes in the liver is associated with how much coffee people drink, researchers say August 25 in Scientific Reports. The more active the gene, called PDSS2, the less coffee people drank. Researchers tracked the coffee-drinking habits of 1,207 people in remote Italian villages and 1,731 people from the Netherlands. The researchers looked for an association between sipping java and people’s genetic makeup. The Dutch quaffed, on average, more than five cups of filtered coffee per day; the Italians sipped about two cups of espresso.
8-25-16 Ultrasound brain zap wakes man from minimally conscious state
Ultrasound brain zap wakes man from minimally conscious state
After a jolt to his thalamus, a man who showed almost no awareness or movement began to communicate, fist-bump, and trying to walk again. What an awakening. A man has been roused from a minimally conscious state by stimulating his brain with ultrasound. The 25-year-old man, who had suffered a severe brain injury after a road traffic accident, progressed from having only a fleeting awareness of the outside world to being able to answer questions and attempt to walk. He was the first person in the world to undergo an experimental procedure that stimulates the thalamus deep inside the brain, using pulses of ultrasound. “It’s only in one person but it’s extremely exciting,” says Martin Monti at the University of California, Los Angeles. Monti and his team have been searching for a way to help people with brain injuries that result in disorders of consciousness, for whom there are few treatments. One kind of disorder is a minimally conscious state, in which a person shows fluctuating signs of awareness, but cannot communicate.
8-25-16 Pneumatic octopus is first soft, solo robot
Pneumatic octopus is first soft, solo robot
US engineers have built the first ever self-contained, completely soft robot - in the shape of a small octopus. Made from silicone gels of varying stiffness, the "octobot" is powered by a chemical reaction that pushes gas through chambers in its rubbery legs. Because of this design, the robot does not need batteries or wires - and contains no rigid components at all. Instead, a sequence of limb movements is pre-programmed into a sort of circuit board built from tiny pipes. These movements aren't good enough, yet, to send the octobot out for a stroll; instead it sits in one place and pumps alternating legs up and down in a very slow, eight-legged can-can. (Webmaster's comment: This is huge compared to the size of the nanobots that will be developed soon.)
8-24-16 Soft robot octopus uses chemical fuel gut to explore untethered
Soft robot octopus uses chemical fuel gut to explore untethered
Freed from tethers and hard circuit board, soft robots are finally able to explore the world’s nooks and crannies. In a dish of water in Cambridge, Massachusetts, a new kind of robot stirs, its tentacles twitching. Squashy and soft, this robot is different from its technological ancestors – Octobot runs without a power cable or rigid electronics, moving autonomously – if still clumsily – through the world. Soft robots have long been heralded as a new class of machine. But their tethers, and the electronics needed to control their movements, have held them back. Octobot is different. Developed by Michael Wehner and colleagues at the Wyss Institute for Bioinspired Engineering, Harvard University, it’s a big step towards fulfilling the potential of soft robots. Standard robots are made of carbon fibre, with plastic and metal circuit boards, copper wiring, high-power rechargeable batteries and electric motors. All this rigidity makes them fit poorly into the human world where our fragile bodies prevail.
8-24-16 Darwin and DNA: How genetics spurred the evolution of a theory
Darwin and DNA: How genetics spurred the evolution of a theory
Mendel and Darwin lived at the same time but never met - yet their ideas about of the natural world would unite into a single revolutionary discovery. Our understanding of evolution today stems from the combination of two very different ideas. One came from a monk who studied pea plants in a Moravian monastery in the 1850s. The other came from a Victorian gentleman who spent five years as a naturalist on a voyage around the world, 20 years previously. Although Gregor Mendel and Charles Darwin were alive at the same time, they never met and Darwin wasn’t aware of Mendel’s work. With hindsight, the union of the two men’s work seems like a marriage made in heaven (or hell, if you’re a creationist). In fact, for many years, it wasn’t obvious that Mendel’s studies of heredity had any relevance to Darwin’s theory of evolution by natural selection. It would take nearly 60 years for this jigsaw to be pieced together and give rise to the “modern synthesis” of evolution, which framed Darwin’s idea in terms of genetics. How exactly did this new understanding arise? And why did it take so long?
8-24-16 Synthetic supermicrobe will be resistant to all known viruses
Synthetic supermicrobe will be resistant to all known viruses
IT’S not finished yet. But if and when it is, it will be the greatest feat of genetic engineering by far. A team in the US is part of the way towards recoding the E. coli bacterium to work with a genetic code that’s different from all other organisms on Earth. That means making more than 62,000 changes to its genome. “We take on projects other groups say are impossibly expensive – or just plain impossible,” says the team leader George Church at Harvard Medical School in Boston, for whom this is one step towards even more ambitious creations. The recoded E. coli could have all kinds of industrial uses. It should be resistant to all existing viruses, and capable of producing proteins unlike any found in nature.
8-24-16 Bacteria display qualities that a mother would love
Bacteria display qualities that a mother would love
Single-celled though they may be, bacteria and other microbes are far from simple. They can thrive in hostile spots — from the acidic, low-oxygen environment of the stomach to boiling hot springs or frozen tundra. Some even breathe rock (see Nealson’s bug). They can adapt rapidly in rough times, switching their metabolic scheme or just going dormant. Bacteria have many admirable qualities that many of us would want for our children: grit, perseverance, flexibility and seemingly limitless creativity (albeit mostly biochemical).
8-24-16 Weapon of bone destruction identified
Weapon of bone destruction identified
Enzyme finding may aid hunt for new anticancer therapies.Mouse femurs with multiple myeloma growing in the bone marrow develop holes and weak spots. Treating mice with a drug that inhibits an enzyme responsible for kick-starting the destruction prevents much of the bone loss. A blood cancer uses a secret weapon for tearing bone apart. That same mechanism may allow breast cancer and other types of tumors to spread to bones, a new study suggests. In patients with the blood cancer multiple myeloma, an enzyme called thymidine phosphorylase sets off a chain reaction that leads to bone destruction, researchers report August 24 in Science Translational Medicine. Drugs that inhibit the enzyme caused mice to lose less bone.
8-24-16 CRISPR inspires new tricks to edit genes
CRISPR inspires new tricks to edit genes
The molecular tool enters a new phase of creative uses. Tweaks to the cutting-edge gene editor known as CRISPR enhance its powers. Scientists usually shy away from using the word miracle — unless they’re talking about the gene-editing tool called CRISPR/Cas9. “You can do anything with CRISPR,” some say. Others just call it amazing. CRISPR can quickly and efficiently manipulate virtually any gene in any plant or animal. In the four years since CRISPR has been around, researchers have used it to fix genetic diseases in animals, combat viruses, sterilize mosquitoes and prepare pig organs for human transplants. Most experts think that’s just the beginning. CRISPR’s powerful possibilities — even the controversial notions of creating “designer babies” and eradicating entire species?— are stunning and sometimes frightening.
8-24-16 The idea that life began as clay crystals is 50 years old.
The idea that life began as clay crystals is 50 years old.
In 1966, a young chemist suggested a radical new theory for how life might have begun on Earth. Fifty years on, we ask if there was any truth in his ideas. A rock is the ultimate example of inanimate, dead matter. After all, it just sits there, and only moves if it is pushed. But what if some minerals are not as stone-dead as we thought? Chemist Graham Cairns-Smith has spent his entire scientific career pushing a simple, radical idea: life did not begin with fiddly organic molecules like DNA, but with simple crystals. It is now 50 years since Cairns-Smith first put forward his ideas about the origin of life. Some scientists have ridiculed them; others have, cautiously or wholeheartedly, embraced them. They have never become mainstream orthodoxy, but they have never quite gone away either. Was there any truth to Cairns-Smith's daring proposal? Did life really come from crystals?
8-24-16 Depression: A revolution in treatment?
Depression: A revolution in treatment?
It's not very often we get to talk about a revolution in understanding and treating depression and yet now doctors are talking about "one of the strongest discoveries in psychiatry for the last 20 years". It is based around the idea that some people are being betrayed by their fiercest protector. That their immune system is altering their brain. The illness exacts a heavy toll on 350 million people around the world. Anti-depressant drugs and psychological treatments, like cognitive behavioural therapy, help the majority of people. But many don't respond to existing therapies and so some scientists are now exploring a new frontier - whether the immune system could be causing depression. "I think we have to be quite radical," says Prof Ed Bullmore, the head of psychiatry at the University of Cambridge.
8-23-16 A bad night’s sleep messes with your brain’s memory connections
A bad night’s sleep messes with your brain’s memory connections
Tests on people’s brains after a night of disruption suggest that sleep is important for clearing space for forming new memories. This is why you feel so awful after a bad night’s sleep – your brain is jammed with yesterday’s news. Christoph Nissen at the University Medical Center in Freiburg, Germany, and his team examined the brains of 20 people after they’d slept well, and after a night of disruption. As well as performing worse in a memory test, they found that, after a bad night’s sleep, people had higher levels of theta brainwaves, and it was easier to stimulate their brains using magnetic pulses. These are both signs of stronger connectivity between neurons. As we form new memories, the connections between our neurons – called synapses – strengthen, building up over the course of a day. “The overall strength of connections between neurons increases with time awake, and eventually reaches a level of saturation after prolonged wakefulness or sleep deprivation,” says Nissen. His team’s findings support the theory that sleep serves to weaken memory connections, making way for new ones. “Without this synaptic downscaling, the brain loses the capacity to form novel connections, impairing the encoding of novel memories,” says Nissen.
8-23-16 Cornea donation may have sex bias
Cornea donation may have sex bias
Transplant failure more likely when women have male donors. Women who receieve corneal transplants are more likely to reject them if their donors are male. Sex matters when it comes to cornea transplants — at least for women. Corneas are low on the list of organs that cause rejection, but it happens more often when women receive corneas from men, researchers report online July 22 in the American Journal of Transplantation. In data from nearly 17,000 transplants, 220 of every 1,000 male-to-female transplants failed versus 180 of every 1,000 sex-matched donations. For men, the donor’s sex didn’t matter.
8-23-16 Secrets of how primates can live at extreme altitude revealed
Secrets of how primates can live at extreme altitude revealed
Gene selection explains how some species of snub-nosed monkeys have adapted to the challenging conditions of their habitat up to 4600 metres above sea level. It can be lonely at the top. Snub-nosed monkeys live at a higher altitude than any other non-human primate – but they are also among the rarest of all primates. The latest genomic analyses may help to explain exactly how they have adapted to life in the thin air found in their habitat and perhaps inform their conservation. Snub-nosed monkeys were once fairly common across Asia, before climate and geological processes conspired against them. Mountain-building activity in the area associated with the formation of the Himalayas and the Tibetan plateau created physical barriers that isolated monkey populations from one another. The deterioration of environmental conditions during the last ice age helped keep those populations apart. By about 300,000 years ago, the monkeys had been isolated for so long that they had split into five distinct species. Golden, black and gray snub-nosed monkeys live in the mountainous forests of southern China, the Tonkin snub-nosed monkey inhabits northern Vietnam and the Myanmar snub-nosed monkey lives in Myanmar. The black snub-nosed monkey has the highest elevational range of any non-human primate. It lives in a small corner of the Tibetan plateau at 3400 to 4600 metres above sea level.
8-23-16 Why bullying is such a successful evolutionary strategy
Why bullying is such a successful evolutionary strategy
It is not just people that bully the vulnerable. Many animals do it too, and in evolutionary terms it may even work. Frodo ruled with an iron fist. He incited fear among his fellow group members. His "demonic streak", as it was later called, started early. From three years old he was throwing rocks at those around him. Frodo, a large-bodied chimpanzee with a recognisable grey streak, would later become the alpha male of his group in Tanzania's Gombe Stream National Park. The primatologist Jane Goodall called him a "real bully". She had even predicted his rise back in 1979, writing: "In about twenty years one of these two brothers probably will become the alpha." All the other chimps feared Frodo, which helped his rise to the top. He even pushed himself on his own mother, and fathered a sickly infant with her, who would not survive for long. "He was aggressive towards all of the other chimps," says anthropologist Michael Wilson of the University of Minnesota in Minneapolis, who first met Frodo in 2001. "A lot of the other males had a bare patch of fur on their lower back side from where Frodo would bite them." Many other primates show similar behaviour to Frodo's. His actions hint at something rather dark about our shared ancestry with chimpanzees. They suggest that bullying your way to the top has a long history, and may even be innate. (Webmaster's comment: There is no excuse for humans bullying even if it is built-in. We have this very large conscious brain and we are fully able to make a conscious decision not to bully. We do not have to be brutes!)
8-23-16 Calcium dementia link is reminder of the dangers of supplements
Calcium dementia link is reminder of the dangers of supplements
An increased risk of dementia in some women taking calcium warns us that supplements marketed as a quick fix for health may not be benign, says Clare Wilson. Taking a daily vitamin or mineral supplement is widely seen as a common-sense way of looking after yourself – a kind of insurance, like wearing a seat belt. But evidence is growing that it might not be such a healthy habit after all. The latest finding is that calcium supplements, taken by many women after the menopause to strengthen their bones, are linked to dementia. Among women who have had a stroke, taking calcium was associated with a seven-fold rise in the number who went on to have dementia. Calcium was also linked with a smaller, non-statistically significant, rise in dementia in women who had not had a stroke. The finding emerged from a study that was not a randomised trial, so it is not the most robust type of medical evidence. The researchers merely counted dementia cases in people who had chosen whether to take calcium, and so the data could be biased. But the results are striking and come on the heels of a previous study that was a randomised trial, which found a link between calcium supplements and a modestly higher risk of heart attacks – suggesting that caution over calcium is indeed warranted. If future research confirms the association with dementia, women would face a horrible dilemma: should they continue to take calcium, staving off bone weakness that can lead to fatal hip fractures, while running an increased risk of one of the most dreaded illness of ageing?
8-23-16 How a tomato plant foils a dreaded vampire vine
How a tomato plant foils a dreaded vampire vine
Dodder sucks the life out of many crops, but one has a gene for fighting back. One of the dodder vines, Cuscuta reflexa, twines over neighboring plants and sucks the life out of them — unless they have a wooden-stake gene. Forget garlic. In real life, a tomato can defeat a vampire. And researchers have now figured out the first step to vegetable triumph. The vampires are slim, tangling vines that look like splats of orange or yellow-green spaghetti after a toddler’s dinnertime tantrum. Botanically, the 200 or so Cuscuta species are morning glories gone bad. In the same family as the heavenly blue garden trumpets, the dodders, as they’re sometimes called, lose their roots about a week after sprouting and never grow real leaves. Why bother when you can drain food and water from the neighbors? A dodder seedling, basically a bare stem, finds that first neighbor by writhing and groping (in slow plant time) toward attractive plant odors. “The Cuscuta can smell its victims,” says Markus Albert of the University of Tübingen in Germany. Depending on the dodder species, victims include asparagus, melons, sugar beets, petunias, garlic, chrysanthemums and oak trees. Even worse for civilization as we know it, some Cuscuta species vampirize coffee plants and grapevines.
8-22-16 Historian traces rise of celebrity hominid fossils
Historian traces rise of celebrity hominid fossils
‘Seven Skeletons’ digs into backstory of famous finds. The Old Man of La Chapelle, a Neandertal skeleton discovered in the early 20th century, is among the fossils highlighted in a new book about how hominid fossils achieve worldwide fame. After decades of research revealing their sophisticated lives, Neandertals still can’t shake their reputation as knuckle-dragging cavemen. And it’s the Old Man of La Chapelle’s fault. The Old Man of La Chapelle was the first relatively complete Neandertal skeleton ever found. Three French abbés discovered the bones in 1908. Soon after, geologist and paleontologist Marcellin Boule analyzed the remains. His conclusion: The ancient individual was a hunched, dim-witted savage. At the time, little was known about human evolution, and Boule’s findings made headlines worldwide. The publicity helped to sear the image of the brutish Neandertal into the public’s mind — so much so that even after subsequent studies determined the Old Man had arthritis and suffered from other abnormalities, it was too late to break the caveman stereotype. The story of the Old Man and six other famous hominid fossils are the focus of Lydia Pyne’s Seven Skeletons. Pyne, a writer and historian, considers how these fossils have shaped our views of human evolution. She also seeks to understand why some fossils end up on T-shirts and postcards, become national symbols and inspire fan fiction while others remain anonymous specimens in museum collections.
8-22-16 Lack of nutrients stalled rebound of marine life post-Permian extinction
Lack of nutrients stalled rebound of marine life post-Permian extinction
Hot seas altered nitrogen cycle, delaying recovery by millions of years. A lack of nutrients may have delayed the recovery of marine ecosystems following the Permian extinction. On northern Ellesmere Island in the Canadian Arctic, light-colored ocean sediments deposited after the extinction contain few nutrients; darker sediments that formed later are nutrient rich. Out-of-reach nutrients could help explain why life on Earth took so long to bounce back from the worst extinction of all time. Analyzing the chemical changes that followed the Permian extinction 252 million years ago, geologists propose that hot sea surface temperatures led to conditions that trapped nitrogen far below the ocean’s sunlit, life-filled layers. The resulting deficiency of the key nutrient helps explain why marine ecosystems took 5 million to 9 million years to recover, millions of years longer than for other mass extinctions, the researchers propose online August 5 in Geology. “It’s equivalent to a farm,” says study coauthor Stephen Grasby, a geochemist at the Geological Survey of Canada in Calgary. “If you’re not throwing fertilizer on the field, the soil becomes nutrient limited and you get less and less plant growth.”
8-21-16 Darwin’s Dogs wants your dog’s DNA
Darwin’s Dogs wants your dog’s DNA
Project seeks to understand genes that govern canine behavior. To learn how genes affect behavior, researchers are asking pet owners to send in their dogs’ DNA and answer questions about behavior, including whether a dog tilts its head or crosses its paws. Going for walks, playing fetch and now participating in genetic research are just a few things people and their dogs can do together. Darwin’s Dogs, a citizen science project headquartered at the University of Massachusetts Medical School in Worcester, is looking for good — and bad — dogs to donate DNA. The project aims to uncover genes that govern behavior, including those involved in mental illness in both people and pets. Looking to dogs for clues about mental illness isn’t as strange as it may seem. Certain breeds are plagued by some of the same diseases and mental health issues that afflict people. Researchers have learned about the genetics of narcolepsy and obsessive compulsive disorder, as well as cancer, blindness and many other ailments from studying purebred dogs. Studies of purebreds are mainly useful when the problem is caused by mutations in a single gene. But most behaviors are the product of interactions between many genes and the environment. A search for those genes can’t be done with a small number of genetically similar dogs. So, Darwin’s Dogs hopes to gather data on a large number of canines, including many breeds and genetically diverse mutts.
8-19-16 Fluorescent jellyfish proteins light up unconventional laser
Fluorescent jellyfish proteins light up unconventional laser
Molecules derived from jellyfish may lead to a new generation of energetically efficient lasers that could improve everything from communications to medical procedures. Safer lasers to map your cells could soon be in the offing – all thanks to the humble jellyfish. Conventional lasers, like the pointer you might use to entertain your cat, produce light by emitting identical photons after they have bounced around inside a cavity. But scaling these up requires lots of energy. Another type of laser – called a polariton laser – works by passing photons back and forth between excited molecules. Unlike in conventional lasers, the photons are released and reabsorbed within the device itself before zooming out as laser light. These can use less energy than conventional lasers, so in theory could lead to more efficient optical communications or medical lasers that are less destructive to living tissue. But there’s a problem: most polariton lasers only work well at extremely low temperatures. Switching the light-producing molecules to ones that operate at room temperature could make them more practical, says Malte Gather at the University of St. Andrews, UK. But the few materials that work at room temperature have light-emitting molecules that sit too close together, interfering with one another instead of producing laser light. So Gather turned to an unusual solution: barrel-shaped fluorescent proteins engineered from jellyfish DNA. Each protein’s cylindrical shell encloses a component that emits light, and keeps those molecules from getting too cosy and interfering with one another.(Webmaster's comment: Our understanding of DNA has led to an explosion of new solutions for many problems.)
8-18-16 Synthetic supermicrobe will be resistant to all known viruses
Synthetic supermicrobe will be resistant to all known viruses
A bacterium with a different genetic code to every other living things is in the pipeline. It will be resistance to all known viruses - and its inventor wants to alter humans in the same way. It’s not finished yet. But if it is, it will be the greatest feat of genetic engineering by far. A team in the US is part-way towards recoding the E. coli bacterium to work with a different genetic code from all other organisms on Earth. That means making more than 62,000 changes to its genome. “We take on projects other groups say are impossibly expensive – or just plain impossible,” says the team leader George Church at Harvard Medical School in Boston, for whom this project is one step towards even more ambitious creations. The recoded E. coli could have all kinds of industrial uses. It should be better in several ways: resistant to all existing viruses, unable to swap genes with other organisms and capable of producing proteins unlike any found in nature.
8-18-16 Eating shuts down nerve cells that counter obesity
Eating shuts down nerve cells that counter obesity
Mouse study offers hints of orexin’s role in weight gain and narcolepsy. Nerve cells that produce a molecule called orexin (also known as hypocretin) may counter obesity, a study of mice suggests. Fractions of a second after food hits the mouth, a specialized group of energizing nerve cells in mice shuts down. After the eating stops, the nerve cells spring back into action, scientists report August 18 in Current Biology. This quick response to eating offers researchers new clues about how the brain drives appetite and may also provide insight into narcolepsy. These nerve cells have intrigued scientists for years. They produce a molecule called orexin (also known as hypocretin), thought to have a role in appetite. But their bigger claim to fame came when scientists found that these cells were largely missing from the brains of people with narcolepsy. People with narcolepsy are more likely to be overweight than other people, and this new study may help explain why, says neuroscientist Jerome Siegel of UCLA. These cells may have more subtle roles in regulating food intake in people without narcolepsy, he adds.
8-18-16 Hoverflies (probably) can’t sense gravity
Hoverflies (probably) can’t sense gravity
Hoverflies (Episyrphus balteatus) use vision and airflow, not gravity, to figure out where they are in space, researchers posit. Hoverflies not only defy gravity, they may not even know it’s there. Insects known for their aerial acrobatics — like hoverflies and dragonflies — have to execute twists and turns with extreme precision. Whether they use gravity to orient themselves and control their altitude has been a mystery. Rather than sending flies into space to test such abilities, Roman Goulard of Aix-Marseille University in France and his colleagues took a basic approach to simulating microgravity: Drop hoverflies (Episyrphus balteatus) in different lab environments and observe how the insects react to free-falling. In a dark box, hoverflies were slow to beat their wings and sense they were falling, and 70 percent crashed. In a light box, the insects had better reaction speed, but many still crashed. Finally, in a box with both light and striped walls (to create a visual pattern), they reacted quickly and crashed only 10 percent of the time. Though impossible to rule out entirely, the insects don't seem to have a means or internal organ (like mammals’ inner ear) to sense acceleration. Instead, hoverflies must rely on just sight and airflow to figure out where they are in space, the researchers argue August 16 in the Journal of Experimental Biology.
8-18-16 DNA traces origins of Iceman's ragtag wardrobe
DNA traces origins of Iceman's ragtag wardrobe
DNA analysis of Oetzi the Iceman's clothes has traced their origin to at least five different species of animal. Among his kit were a hat of brown bear skin and a quiver made from roe deer. Despite being well preserved and studied, the 5,300-year-old mummy's various leather items had not all been identified at the species level. These findings, published in Scientific Reports, reveal a mix of wild-hunted animals with sheep, goat and cattle related to modern domestic breeds.
8-17-16 Genetic diversity data offers medical benefits
Genetic diversity data offers medical benefits
Study finds human DNA can vary in more than 7 million spots. A study of more than 60,000 people’s genes reveals previously hidden genetic diversity. A large study of human genetic variation finds more than 7 million spots where one person’s DNA can differ from another’s. Analyses of such variants, compiled from cataloging the genes from more than 60,000 people, are already offering doctors helpful insights into diseases such as schizophrenia and some heart conditions. Researchers from the Exome Aggregation Consortium first presented their analysis of the ExAC database online at bioRxiv.org last year (SN: 12/12/15, p. 8). Now, the project is getting its official debut in the Aug. 18 Nature.
8-18-16 How noise hinders kids' language skills
How noise hinders kids' language skills
More than 40 years ago, psychologists found signs that children living in noisy places were having trouble learning to read. They suspected that the noise interfered with language learning. Now, their suspicions have been confirmed, this time in the lab. The original experiment, published in 1973, looked at children living in four unique apartment buildings in New York City. The Bridge Apartments, on the Manhattan side of the George Washington Bridge, sit directly on top of Interstate 95. At the time of the study, the researchers wrote, "open highway vents and vertical surfaces of the buildings produce[d] high noise levels and an 'echo chamber' effect." On the bottom floor of the buildings, the noise was as loud as having a blender on all the time — 85 decibels. On higher floors in the building, where the noise was less loud, the children had fewer reading difficulties. But the apartments on the top floor also had higher rents, and family income is associated with reading ability. Over the years, scientists have wondered whether noise really is linked to language difficulties. Now, lab experiments have borne it out: A recent study finds that toddlers have trouble learning words when there's too much background noise. "A lot of studies are done in very quiet environments, which isn't really what kids experience out in the real world," said study author Brianna McMillan, a graduate student at University of Wisconsin, Madison. (Webmaster's comment: Start by turning off the TV.)
8-17-16 Bunnies helped a great civilisation in ancient Mexico thrive
Bunnies helped a great civilisation in ancient Mexico thrive
A pen for rabbits and hares and butchering tools unearthed in the city of Teotihuacan suggest the animals played a key role in its well-developed economy. The trade in bunnies helped power an ancient economy. Teotihuacan, an ancient city in central Mexico, was an advanced metropolis where most people lived in apartment complexes. The city reached its peak between the first century and 550 AD. With about 100,000 residents, it was the largest urban area in the Americas at the time, of a similar scale and sophistication as other ancient centres like Alexandria and Rome. But until now, it has been a mystery what kinds of animals supported this complex society. “One of the big puzzles for the pre-Colombian Americas has always been the lack of domesticated animals,” says David Carballo at Boston University. Other than managing dogs and turkeys, Mesoamericans didn’t appear to have the close relationships with animals that sustained ancient peoples in Africa and Europe. Now it seems that raising cottontails and jackrabbits may have given the city a reliable source of meat and fur. Linda Manzanilla at the National Autonomous University of Mexico in Mexico City and colleagues have uncovered an apartment compound that seems to have belonged to rabbit breeders and butchers. The team found rooms littered with rabbit bones, as well as obsidian blades for butchering and for scraping skins.
8-17-16 Oldest jewellery in East Asia is crafted 37,000-year-old shell
Oldest jewellery in East Asia is crafted 37,000-year-old shell
Ancient artefacts in an East Timor cave reveal that early human settlers here were more advanced than thought, fishing the deep sea and making ornaments. Shell jewellery and ornaments up to 42,000 years old, discovered in East Timor, have overturned long-held assumptions that the first inhabitants of South-East Asia were culturally unsophisticated. The finds represent the oldest evidence of ornament and jewellery-making in the region. The most ancient example of shell jewellery is 82,000 years old and was found in Morocco, although some shell art may date even further back. As humans migrated out of Africa, shell jewellery started appearing in the European archaeological record from about 50,000 years ago. Humans moved into East Asia around the same time, but the area has yielded few examples of personal ornamentation of such antiquity. Some researchers had speculated that the early settlers abandoned crafts and so were less technologically advanced than their European counterparts.
8-17-16 Marsupial lion’s primate-like forearms made it a unique predator
Marsupial lion’s primate-like forearms made it a unique predator
The primate-like forearms of the marsupial lion could have allowed deft use of its formidable claws – and made it unlike any predator seen today. Kangaroos in prehistoric Australia faced a fearsome threat. The marsupial lion had sharp teeth, crushing jaws – and manoeuvrable, primate-like forearms that could have allowed it to slash at prey with large, retractable thumb claws. The creature, Thylacoleo carnifex, lived during the Pleistocene – which began about 2.6 million years ago – and clocked in at around 100 to 160 kilograms until it went extinct around 30,000 years ago. It probably looked like a cross between a small bear and a wombat, says Stephen Wroe at the University of New England in Armidale, Australia. Its cheek teeth — the dental hallmark of a hunter — mark it as a fierce predator. “In a real, card-carrying, no-bullshit mammalian carnivore, what you see are very large, vertically slicing blades,” says Wroe – like the ones in the marsupial lion’s jaws. “These are the teeth that are used to slice through thick, fibrous flesh and skin.” The marsupial lion was capable of taking down herbivores much larger than itself, including prehistoric kangaroos. The big question is how the animal did it.
8-17-16 Americas’ hookup not so ancient after all
Americas’ hookup not so ancient after all
Latest volley in Panama land bridge debate pegs age at 3 million years. The age of the narrow strip of land that links North and South America is at the center of a debate among scientists. The rocky coasts of the Isthmus of Panama alter ocean currents and the world’s climate. A debate over when the gap between North and South America closed has opened a rift in the scientific community. Analyzing existing data from ancient rocks, fossils and genetic studies, a group of researchers has assembled a defense of the conventional view that the Isthmus of Panama formed around 3 million years ago. That work rebuts papers published last year that concluded that the continental connection started millions of years earlier (SN: 5/2/15, p. 10). The authors of the new paper, published August 17 in Science Advances, caution against the “uncritical acceptance” of the older formation date.
8-17-16 Giant ancient supervolcanoes threw rock right across Australia
Giant ancient supervolcanoes threw rock right across Australia
Massive eruptions when New Zealand ripped away from Australia were tens to hundreds of times stronger than anything ever recorded in human history. The east coast of Australia was once lined by volcanoes that were so explosive they could shoot sand-sized particles 2300 kilometres – all the way across to the west coast. The volcanic activity occurred 100 million years ago, at a time when New Zealand began tearing away from Australia’s eastern edge. Until recently, the only evidence of the scale of these eruptions were the 20-kilometre-wide dormant craters and the solidified lava flows left behind. But now, Milo Barham at Curtin University in Western Australia and his colleagues have found that these eastern Australian volcanoes flung material to the other side of the country.
8-17-16 New species of fossil dolphin found
New species of fossil dolphin found
Scientists have identified a new species of dolphin that lived 25 million years ago. The extinct animal has been described through re-examination of a specimen that's been in a museum collection since 1951. Researchers think it is a relative of the endangered South Asian river dolphin, offering clues to the evolutionary history of modern species. The dolphin swam in sub-arctic marine waters about 25 million years ago, according to the new study's authors Alexandra Boersma and Nicholas Pyenson, who are based at the Smithsonian. Based on the age of nearby rocks, the scientists estimated that Arktocara came from the late Oligocene epoch, around the time that ancient whales diversified into two groups - the baleen whales, which include blue whales and humpbacks, and the toothed whales, which include sperm whales, porpoises and dolphins.
8-17-16 When it comes to antimicrobial resistance, watch out for wildlife
When it comes to antimicrobial resistance, watch out for wildlife
Bacterial genes that best drugs, disinfectants turning up in guts of all sorts of animals. Northern elephant seals in California are some of the diverse wild animals that researchers have found with microbes carrying genes for resisting drugs and disinfectants. It’s time to go wild studying antimicrobial resistance, a research team says. Most analyses of how microbes come to laugh off the drugs and disinfectants that should kill them have focused on people in hospitals or livestock on farms, says behavioral ecologist Kathryn Arnold of the University of York in England. Yet a growing number of studies — in crows, elephant seals, voles and other wild animals — are raising big questions about where wildlife fits into the increasing threat of antimicrobial resistance. Genes for resistance are showing up in microbes flourishing in the guts and other parts of wild animals. How those genes get there and where they might go now needs serious attention, Arnold and colleagues argue August 17 in a Biology Letters review of wildlife-related papers.
8-16-16 Female fish have a fail-safe for surprise sperm attacks
Female fish have a fail-safe for surprise sperm attacks
Female ocellated wrasse lay their eggs in an algae nest, and colorful nesting males quickly fertilize them. A female’s ovarian fluid can favor sperm from her chosen mate when there’s sperm competition, researchers find. Some guys really know how to kill a moment. Among Mediterranean fish called ocellated wrasse (Symphodus ocellatus), single males sneak up on mating pairs in their nest and release a flood of sperm in an effort to fertilize some of the female’s eggs. But female fish may safeguard against such skullduggery through their ovarian fluid, gooey film that covers fish eggs. Suzanne Alonzo, a biologist at Yale University, and her colleagues exposed sperm from both types of males to ovarian fluid from female ocellated wrasse in the lab. Nesting males release speedier sperm in lower numbers (about a million per spawn), while sneaking males release a lot of slower sperm (about four million per spawn). Experiments showed that ovarian fluid enhanced sperm velocity and motility and favored speed over volume. Thus, the fluid gives a female’s chosen mate an edge in the race to the egg, the researchers report August 16 in Nature Communications.
8-16-16 Lizard mom’s microbiome may protect her eggs
Lizard mom’s microbiome may protect her eggs
Female striped plateau lizards may be able to protect their eggs with microbes, a group of scientists is finding. Human babies born via cesarean section miss out on an opportunity to pick up beneficial microbes that other babies get when they take a trip through mom’s vagina. And even though the scientific jury’s still out on whether this is a good idea, some parents have been wiping their C-section babies down with vaginal fluid in the hopes that their newborns might get some of those microbial benefits, Laura Sanders reported earlier this yearover at the Growth Curve blog. Microbial transfer from mom to offspring happens in a lot of species, but researchers are more familiar with how species that give live birth do this than those that lay eggs, biologist Stacey Weiss of the University of Puget Sound in Tacoma, Wash., noted August 1 at the 53rd Annual Conference of the Animal Behavior Society. Researchers have found that moms can transfer microbes right into the egg itself before it is laid or onto or near the egg after laying.
8-16-16 Viruses 'more dangerous in the morning'
Viruses 'more dangerous in the morning'
Viruses are more dangerous when they infect their victims in the morning, a University of Cambridge study suggests. The findings, published in PNAS, showed viruses were 10 times more successful if the infection started in the morning. And the animal studies found that a disrupted body clock - caused by shift-work or jet lag - was always vulnerable to infection. The researchers say the findings could lead to new ways of stopping pandemics. Viruses - unlike bacteria or parasites - are completely dependent on hijacking the machinery inside cells in order to replicate. But those cells change dramatically as part of a 24-hour pattern known as the body clock.
8-16-16 Genes that control toxin production in C. difficile ID’d
Genes that control toxin production in C. difficile ID’d
New finding could lead to better ways to disarm gut-wrenching superbug. Unraveling the toxin-making genetic pathway in Clostridium difficile may help scientists design nonantibiotic therapies to fight the superbug. A new genetic discovery could equip researchers to fight a superbug by stripping it of its power rather than killing it outright. Scientists have identified a set of genes in Clostridium difficile that turns on its production of toxins. Those toxins can damage intestinal cells, leading to diarrhea, abdominal pain and potentially life-threatening disease. Unlocking the bug’s genetic weapon-making secret could pave the way for new nonantibiotic therapies to disarm the superbug while avoiding collateral damage to other “good” gut bacteria, researchers report August 16 in mBio.
8-16-16 Mystery of déjà vu explained – it’s how we check our memories
Mystery of déjà vu explained – it’s how we check our memories
The phenomenon seems to be a sign of a healthy memory that forms accurate memories, déjà vu brain scans have revealed for the first time. Feel like you’ve read this before? Most of us have experienced the eerie familiarity of déjà vu, and now the first brain scans of this phenomenon have revealed why – it’s a sign of our brain checking its memory. Déjà vu was thought to be caused by the brain making false memories, but research by Akira O’Connor at the University of St Andrews, UK, and his team now suggests this is wrong. Exactly how déjà vu works has long been a mystery, partly because its fleeting and unpredictable nature makes it difficult to study. To get around this, O’Connor and his colleagues developed a way to trigger the sensation of déjà vu in the lab.
8-15-16 Herpes infections are worse if contracted at the end of the day
Herpes infections are worse if contracted at the end of the day
Our circadian rhythms affect our ability to fight off infection, and a study in mice suggests shift workers may be particularly vulnerable to viruses. How likely are you to get ill? Check the clock. A study of circadian rhythms has revealed that mice are more susceptible to infections at certain times of day. Akhilesh Reddy at the University of Cambridge and his team made this discovery by exposing mice to the herpes virus. They found that the virus replicated 10 times as much in mice that were infected at the end of their day, rather than at the beginning. “The time of day of infection can have a major influence on how susceptible we are to disease,” says Reddy. His team also tried the experiment in mice with disrupted body clocks, and found consistently high levels of virus activity in these mice, regardless of the time of infection – a result with worrying implications for people with disrupted bodyclocks. “This indicates that shift workers, who work some nights and rest some nights, will be more susceptible to viral diseases,” says team-member Rachel Edgar. “If so, then they could be prime candidates for receiving annual flu vaccines.” Shift workers are known to be more prone to health problems, ranging from infections to chronic diseases.
8-15-16 Without oxygen from ancient moss you wouldn’t be alive today
Without oxygen from ancient moss you wouldn’t be alive today
The earliest terrestrial plants, such as moss, made a surprising contribution to the levels of oxygen in the atmosphere some 400 million years ago. Earth’s air is only breathable today because of moss-like plants that colonised the land 470 million years ago. The moss enriched the atmosphere with oxygen and triggered a cycle that maintained its levels, paving the way to complex life. Oxygen in its current form first appeared on Earth 2.4 billion years ago in what has become known as the Great Oxidation Event. But it was not until around 400 million years ago that oxygen in the atmosphere approached present day levels. Scientists have long debated what caused this shift, without which humans could not have evolved. A team from the University of Exeter, in the UK, used computer simulations to show how the first land plants contributed to the Earth’s oxygen. The earliest terrestrial plants were simple bryophytes, such as moss, which lack vein-like systems to transport water and minerals. Factoring the properties of modern bryophytes into the simulations indicated that thanks to the ancient mosses, modern levels of atmospheric oxygen would have been achieved by 420 to 400 million years ago. The emergence of the plants eventually led to a stable and self-sustaining cycle of oxygen flowing between sedimentary rocks, living things and the atmosphere.
8-15-16 World’s oldest ocean crust dates back to ancient supercontinent
World’s oldest ocean crust dates back to ancient supercontinent
The rock at the bottom of the eastern Mediterranean is 340 million years old, and could yield secrets of the formation – and breakup – of the ancient Pangaea continent. The oldest patch of undisturbed oceanic crust on Earth may lie deep beneath the eastern Mediterranean Sea – and at about 340 million years old, it beats the previous record by more than 100 million years. Earth’s outermost shell can be billions of years old on land, but most oceanic crusts are younger than 200 million years. Understanding where they developed can help us figure out what Earth looked like as continents formed, broke apart, and shifted around the globe hundreds of millions of years ago. Earth’s crust is well-studied, but there are geologically complex places where scientists don’t agree on its nature – whether it’s oceanic or continental, and its age – says Roi Granot at Ben-Gurion University of the Negev in Israel. “The Mediterranean Sea is one of them,” he says. “And now it seems that we know what it is.”
8-15-16 Two stationary kinds of bacteria can move when mixed
Two stationary kinds of bacteria can move when mixed
Speed increases as pair evolves together, study finds. A Pseudomonas fluorescens bacterium and its colony get stranded when alone on dry surfaces, but mix in a different stationary species and evolution gets them moving. Strand a fish on a tree stump, and neither swims away. But mixing two kinds of soil bacteria that are stationary on dry surfaces allows the combo — by means not yet clear— to expand unusually quickly, multiplying and oozing as a colony across a firm laboratory agar surface. Over generations, the pair gets faster, Lucy McCully of the University of Massachusetts Dartmouth said August 6 at the 2nd American Society for Microbiology Conference on Experimental Microbial Evolution. She and coauthor Mark Silby are interested in what happens when bacterial species mingle and evolve together. Bacteria often get studied in colonies of single kinds, but real soil is a stew of many ingredients.
8-12-16 ‘Promiscuous’ enzymes can compensate for disabled genes
‘Promiscuous’ enzymes can compensate for disabled genes
Bacteria devise metabolic work-around when important biochemical reactions are thwarted. When E. coli loses genes that make important enzymes, other enzymes will find a new way to do the same job. When bacteria lose genes needed to make enzymes for important chemical reactions, defeat isn’t inevitable. Sometimes other enzymes will take on new roles to patch together a work-around chain of reactions that does the job, biologist Shelley Copley reported August 4 at the 2nd American Society for Microbiology Conference on Experimental Microbial Evolution. Bacteria that can adapt in this way are more likely to survive when living conditions change, passing along these new tricks to their descendants. So studying these biochemical gymnastics is helping scientists to understand how evolution works on a molecular level. Working with different strains of Escherichia coli bacteria, Copley and colleagues deleted genes responsible for making crucial enzymes. The team then watched the microbes replicate for many generations to see how they worked around those limitations.
8-12-16 For bacteria, assassination can breed cooperation
For bacteria, assassination can breed cooperation
Microbe’s use of toxic weaponry creates single-strain clumps. Bacteria assassinating each other when crowded together ironically can favor the evolution of cooperation. When a Vibrio cholerae bacterium jostles neighbors in crowds on crab shells, it fires a spring-loaded toxin injection. Siblings with the same immunity genes don’t die, but genetically different strains of V. cholerae can succumb. In both laboratory battles and computer simulations, these neighbor-to-neighbor harpoonings over time can separate a random mix of strains into a patchy landscape of same-strain clumps. The change from all mixed up to irregular patches works like a separation process of phases of metals (called the Model A order-disorder transition) and has not been reported before in living things, William Ratcliff of Georgia Institute of Technology in Atlanta said August 5 at the 2nd American Society for Microbiology Conference on Experimental Microbial Evolution.
8-12-16 First wearable brain scanner to probe people with amazing gifts
First wearable brain scanner to probe people with amazing gifts
From incredible memories, to exceptional mathematical or musical ability, a deep-brain scanner could reveal what’s going on inside savants’ heads. Scientists have developed the first wearable PET scanner – allowing them to capture the inner workings of the brain while a person is on the move. The team plans to use it to investigate the exceptional talents of savants, such as perfect memory or exceptional mathematical skill. All available techniques for scanning the deeper regions of our brains require a person to be perfectly still. This limits the kinds of activities we can observe the brain doing, but the new scanner will enable researchers to study brain behaviour in normal life, as well providing a better understanding of the tremors of Parkinson’s disease, and the effectiveness of treatments for stroke. Positron emission tomography scanners track radioactive tracers, injected into the blood, that typically bind to glucose, the molecule that our cells use for energy. In this way, the scanners build 3D images of our bodies, enabling us to see which brain areas are particularly active, or where tumours are guzzling glucose in the body. To adapt this technique for people who are moving around, Stan Majewski at West Virginia University in Morgantown and his colleagues have constructed a ring of 12 radiation detectors that can be placed around a person’s head. This scanner is attached to the ceiling by a bungee-cord contraption, so that the wearer doesn’t feel the extra weight of the scanner.
8-12-16 Human-animal chimeras may be key to us living healthier lives
Human-animal chimeras may be key to us living healthier lives
The US is considering a resumption of funding for the creation of human-animal chimeras. That’s good news for all of us. There’s a one-in-five chance you’ll die of heart disease. But imagine if as soon as your heart showed signs of disease, you got whisked into hospital and given a healthy young heart that was a perfect match for you. If we had a cheap and unlimited supply of healthy organs for transplant, it wouldn’t just transform the lives of desperately ill people who wait for years for organs – often only to get ones in a poor condition. It would also help people who doctors today don’t even consider for a transplant. It could become normal to have 80-year-olds running around with organs as healthy as those of people a quarter their age. Will this vision ever become a reality? Governments and companies are spending billions on research into stem cells and regenerative medicine. One of the aims is to grow replacement organs outside the body.
8-12-16 Depression’s genetic origins
Depression’s genetic origins
Biological clues about the roots of the blues. While researchers have identified genes associated with many debilitating diseases, the biological underpinnings of depression have remained elusive—until now. A large-scale study that tapped into crowdsourced data discovered a trove of 17 different genetic variations linked to depression in people of European ancestry, reports The Guardian (U.K.). In order to pinpoint genetic variants, which may have a very subtle influence on a person’s overall depression risk, a team of researchers analyzed saliva samples of more than 300,000 people collected by the genetic-profiling company 23andMe. Of those people, 75,607 anonymously reported being diagnosed or treated for depression. The researchers combined their results with data from another study involving roughly 9,000 people with depression and 9,500 healthy adults. They found the genetic variations linked to depression are spread across 15 regions of the genome, including several sites in or around genes involved in brain development. The study doesn’t prove these gene variations cause depression, but it could alter perceptions about the condition and lead to better treatments. “It just underscores that depression really is a brain disease,” says researcher Roy Perlis. “Depression is about biology, and I think that will be helpful for some people in reducing stigma.”
8-12-16 Regeneration proteins offer clue to restoring hearing loss
Regeneration proteins offer clue to restoring hearing loss
Sea anemones’ repair molecules fix sound-sensing cells in mice. Starlet sea anemones reproduce by tearing themselves in two and regenerating their missing halves. Researchers are hacking this special ability to find possible treatments for hearing loss. Understanding sea anemones’ exceptional healing abilities may help scientists figure out how to restore hearing. Proteins that the marine invertebrates use to repair damaged cells can also repair mice’s sound-sensing cells, a new study shows. The findings provide insights into the mechanics of hearing and could lead to future treatments for traumatic hearing loss, researchers report in the Aug. 1 Journal of Experimental Biology.
8-12-16 The nose: A trove of new antibiotics?
The nose: A trove of new antibiotics?
In their quest for new antibiotics to fight drug-resistant “superbugs,” researchers have discovered a promising candidate right under our noses—or, more precisely, among the bacteria that live inside them. While mouth or gut microbes feast on a constant flow of food, nasal bacteria dwell in a kind of wasteland, and as a result they have developed potent weapons to compete for scant nourishment and ensure their survival. After raiding this antimicrobial arsenal, a team in Germany found a bacteria, Staphylococcus lugdunensis, that produces the chemical compound lugdunin, possibly a powerful antibiotic against resistant bacterial strains that threaten to kill 10 million people a year by 2050. Tests in mice showed that lugdunin is effective against a range of potentially deadly infections, including methicillin-resistant Staphylococcus aureus, or MRSA, which is acquired in hospitals and sickens some 90,000 Americans annually. Medical use is a long way off, but ultimately the approach used to find lugdunin may be more significant than the compound itself. Many antibiotics derive from soil bacteria, but the human microbiome—microorganisms living on and inside the body—is a new frontier of possibilities. As study author Andreas Peschel tells the Los Angeles Times, “It was totally unexpected to find a human-associated bacteria to produce an antibiotic.”
8-12-16 400-year-old Greenland shark ‘longest-living vertebrate’
400-year-old Greenland shark ‘longest-living vertebrate’
Greenland sharks are now the longest-living vertebrates known on Earth, scientists say. Researchers used radiocarbon dating to determine the ages of 28 of the animals, and estimated that one female was about 400 years old. The team found that the sharks grow at just 1cm a year, and reach sexual maturity at about the age of 150.
8-11-16 Sleep deprivation hits some brain areas hard
Sleep deprivation hits some brain areas hard
Some regions resist drowsiness, while others falter without slumber. Brain regions involved with problem solving are especially slow to respond when sleep-deprived, a new study shows. Pulling consecutive all-nighters makes some brain areas groggier than others. Regions involved with problem solving and concentration become especially sluggish when sleep-deprived, a new study using brain scans reveals. Other areas keep ticking along, appearing to be less affected by a mounting sleep debt. The results might lead to a better understanding of the rhythmic nature of symptoms in certain psychiatric or neurodegenerative disorders, says study coauthor Derk-Jan Dijk. People with dementia, for instance, can be afflicted with “sundowning,” which worsens their symptoms at the end of the day. More broadly, the findings, published August 12 in Science, document the brain’s response to too little shut-eye.
8-11-16 The desperate search for a cure for a deadly brain-eating amoeba
The desperate search for a cure for a deadly brain-eating amoeba
The deaths hit the headlines every summer, sometimes five or six of them across the country. They're newsworthy for their rarity and for how innocuous the events leading up to them are — it's usually a young person who was swimming in a lake, got some water up their nose, and within days, was dead. The cause is an amoeba called Naegleria fowleri, which when it infects the brain, causes massive swelling that is almost always fatal. Over the past half-decade, 137 people in the U.S. have died of the infection. That rarity means that hardly any research money exists to find treatments. The best line of attack at present is a combination of drugs designed for other conditions. "Even with the best drug combinations, the fatality rate is over 98 percent," said Dennis Kyle, an infectious disease researcher at the University of South Florida. "People are dying from this disease all the time, and we really have nothing to treat it effectively."
8-11-16 Aphrodisiac virus makes plants super-attractive to bumblebees
Aphrodisiac virus makes plants super-attractive to bumblebees
The benefits of a viral infection for tomato plants may outweigh the costs – infected plants attract more pollinators and therefore produce more seeds. Going viral is a good thing. Viral infections can help some plants attract more pollinators and produce more seeds, essentially boosting – rather than hurting – their evolutionary fitness, a new study has found. Plants are known to emit volatile chemicals that deter herbivores or attract pollinators or seed dispersers. Some viruses can change those volatiles to attract insects, such as aphids, that damage plants but help transmit the virus between them. Now, a team of researchers lead by John Carr from the University of Cambridge has shown in greenhouse experiments that a cucumber mosaic virus can change the types and amounts of chemicals emitted by an infected tomato plant, so that it attracts more bumblebees to pollinate it. As a result, the plants in their experiments produced more seeds. Without pollination, the virus affected the plants negatively, decreasing their seed production, compared with non-infected plants. But when bumblebees were present, it had the opposite effect.
8-11-16 Sneaky virus helps plants multiply, creating more hosts
Sneaky virus helps plants multiply, creating more hosts
Infected tomato plants give off special aroma that lures pollinators. Plants infected with cucumber mosaic virus, like this tomato plant, are often stunted and blemished. But the virus appears to help the sick plants reproduce by making them more attractive to bees. Instead of destroying its leafy hosts, one common plant virus takes a more backhanded approach to domination. It makes infected plants more attractive to pollinators, ensuring itself a continued supply of virus-susceptible plant hosts for generations to come. The strategy might be a way for the virus to discourage resistance from building up in the plant population, University of Cambridge biologist John Carr and colleagues report online August 11 in PLOS Pathogens.
8-11-16 Study ranks Greenland shark as longest-lived vertebrate
Study ranks Greenland shark as longest-lived vertebrate
New radiocarbon dating of eye lenses suggests life span up to 392 years. A Greenland shark might outdo all other vertebrates in longevity, a new study says. The latest in birthday science proposes that the vertebrate with the longest life span yet measured is the mysterious Greenland shark. Dating based on forms of carbon found in sharks’ eye lenses suggests that a large female Somniosus microcephalus was about 392 years old (give or take 120 years) when she died, says marine biologist Julius Nielsen of University of Copenhagen. Even with that uncertainty, the shark outdoes what Nielsen considers the previous record holder: a bowhead whale estimated to have lived 211 years.
8-11-16 World’s oldest vertebrate is a shark that lives for 500 years
World’s oldest vertebrate is a shark that lives for 500 years
Deep-sea-living Greenland sharks can live for hundreds of years, longer than any other vertebrate, and females don’t reach breeding age until they are 150. Fish that were alive during the Age of Enlightenment are still swimming strong. A Greenland shark has lived at least 272 years, making the species the longest-lived vertebrate in the world – smashing the previous record held by a 211-year-old bowhead whale. But it may have been as old as 500 years. “We definitely expected the sharks to be old, but we didn’t expect that it would be the longest-living vertebrate animal,” says Julius Nielsen of the University of Copenhagen, Denmark. Living deep in the North Atlantic and the frigid surface waters of the Arctic, Greenland sharks have a stable environment and grow just a few centimetres per year. Despite their slow growth, though, they reach more than 5 metres in length and are often the apex predator in their ecosystem.
8-11-16 Colugo genome reveals gliders as primate cousins
Colugo genome reveals gliders as primate cousins
A new genetic study adds to evidence that tree-dwelling colugos are closely related to primates. Primates may have some high-flying relatives. Colugos, small mammals that glide from treetop to treetop in forests throughout Southeast Asia, have an evolutionary history that's long been debated. Their teeth look similar to tree shrews' teeth, while other skull and genetic features resemble those of primates. (Past studies have even linked colugos to bats and other insect-eating mammals.) Now, in an effort to settle the debate, William Murphy, a geneticist at Texas A&M University in College Station, and his colleagues have deciphered the genome of a male Sunda colugo (Galeopterus variegatus) from West Java, Indonesia. Comparing colugo DNA to 21 other mammal genomes, the team found that colugos are most closely related to primates, while tree shrews took different evolutionary paths to arrive at similar traits. There are also changes in genes related to vision and gliding that are unique to colugos, the researchers report August 10 in Science Advances.
8-10-16 Simple lab life makes an evolutionary leap in a few generations
Simple lab life makes an evolutionary leap in a few generations
It only takes a few generations for snowflake lab yeasts to adopt distinct lifestyles – a great leap forward in early evolution of life. Just a few generations after evolving multicellularity, lab yeasts have already settled into at least two distinct lifestyles. The discovery suggests that organisms can swiftly fill new niches opened up by evolutionary innovations, just as the first multicellular animals appear to have done on Earth, hundreds of millions of years ago. In 2011, evolutionary biologist Michael Travisano and his student William Ratcliff at the University of Minnesota in St Paul made single-celled brewer’s yeast evolve into multicellular forms in the lab. They did that by centrifuging yeast cultures and selecting the fastest-settling yeasts to found the next generation. Since clumps of cells settle faster than single cells, this quickly led to multicellular “snowflakes”. When another of Travisano’s students, Maria Rebolleda-Gomez, looked at Ratcliff’s multicellular strains, she noticed that some snowflakes were up to 10 times larger than others. So she took individual cells from large and small snowflakes in Ratcliff’s original samples and grew them into new multicellular snowflakes.
8-10-16 First real-time look at genes switching off in live human brains
First real-time look at genes switching off in live human brains
A radioactive tracer has let researchers watch patterns of gene activity across healthy brains, as well as in those of people with schizophrenia. The switching-off of genes in the human brain has been watched live for the first time. By comparing this activity in different people’s brains, researchers are now on the hunt for abnormalities underlying disorders such as Alzheimer’s disease and schizophrenia. To see where genes are most and least active in the brain, Jacob Hooker at Harvard Medical School and his team developed a radioactive tracer chemical that binds to a type of enzyme called an HDAC. This enzyme deactivates genes inside our cells, stopping them from making the proteins they code for. When injected into people, brain scans can detect where this tracer has bound to an enzyme, and thus where the enzyme is switching off genes.
8-10-16 Scientists get a glimpse of chemical tagging in live brains
Scientists get a glimpse of chemical tagging in live brains
A new radioactive tracer molecule shows where chemical tags, called epigenetic marks, are made in the brains of healthy people. Shown is the epigenetic activity in a volunteer’s brain imaged 60 to 90 minutes after injection of the tracer. For the first time scientists can see where molecular tags known as epigenetic marks are placed in the brain. These chemical tags — which flag DNA or its protein associates, known as histones —don’t change the genes, but can change gene activity. Abnormal epigenetic marks have been associated with brain disorders such as Alzheimer’s disease, schizophrenia, depression and addiction.
8-10-16 Best look yet at how our brain's sewage system flushes out waste
Best look yet at how our brain's sewage system flushes out waste
A souped-up MRI scanner has revealed the forces that push waste products out of our brains, a process that may be crucial for preventing Alzheimer's disease. Researchers have had the best look yet at microscopic vessels that take waste away from nerve cells in the brain. The first clear picture of this network, called the glymphatic system, came in 2012 from experiments in mice. The network seems to ramp up when we sleep, removing unwanted metabolic by-products and waste proteins like beta-amyloid, but many details, including the exit route this waste takes, are still unclear. To examine the system in people, Vesa Kiviniemi of the University of Oulu in Finland and his colleagues have developed a souped-up form of MRI scanning that takes 20 times as many photos per second. With this high resolution they followed the biological trash as it was flushed through the network.
8-10-16 Humans may have taken different path into Americas than thought
Humans may have taken different path into Americas than thought
A passage between the colossal glaciers that once covered the North American Arctic, shown here in present day, may have contained too little vegetation and wildlife to nourish the earliest human migrations into the rest of the Americas. The first American pioneers could not have reached the New World the way most textbooks say they did, researchers conclude in a new study. An open corridor through the ice-covered North American Arctic was too barren to support human migrations before around 12,600 years ago, fossilized DNA evidence suggests. “If you look at a textbook about the earliest people in the Americas, you’ll see an arrow going from Siberia, into Alaska and through this interior ice-free corridor,” says study coauthor Eske Willerslev, an evolutionary geneticist at the University of Copenhagen. “This whole schoolbook example of how the Americas were populated seems to fall apart.” By analyzing DNA embedded inside ancient lakebeds, Willerslev and colleagues reconstructed the ecological history of a segment of the passage. Though it was ice-free during the earliest human migrations — dating back at least 14,700 years — for thousands of years, the passage contained too little vegetation and wildlife to feed the travelers, the researchers conclude in the Aug. 10 Nature. The findings, which have drawn skepticism from other experts who say the researchers overlooked other evidence, support the idea that the first Americans instead traveled down the coast.
8-10-16 First Americans must have arrived by sea, not via Alaska
First Americans must have arrived by sea, not via Alaska
A study of prehistoric DNA has challenged the established theory that says people first reached the Americas via a land bridge in the Arctic. A study of prehistoric DNA has challenged the established theory of how people first reached the Americas. It suggests ice age people cannot have migrated to America on a land corridor between two glaciers as it was “biologically unviable”. Conventional wisdom had it that the settlement of the Americas happened as people moved south through what is now Canada after two glaciers started to recede. But analysis of DNA extracted from a key pinch-point suggests this was not possible as resources vital to human survival would not have been available in the ice-free corridor. Researchers suggest it is likely that people travelled by sea instead. An international team of researchers used ancient DNA extracted from a crucial point in the corridor to investigate how its ecosystem evolved as the glaciers began to retreat. They created a comprehensive picture showing how and when different flora and fauna emerged and the once ice-covered landscape became a viable passageway. No prehistoric reconstruction project like it has been attempted before.
8-10-16 The kindness paradox: Why be generous?
The kindness paradox: Why be generous?
Humans are one of the rare animals to be altruistic. An ancient form of giving holds secrets about why we help one another without any promise of reward. LIFE isn’t easy as a Maasai herder on the Serengeti plain in eastern Africa. At any moment, disease could sweep through your livestock, the source of almost all your wealth. Drought could parch your pastures, or bandits could steal the herd. No matter how careful you are, or how hard you work, fate could leave you destitute. What’s a herder to do? The answer is simple: ask for help. Thanks to a Maasai tradition known as osotua – literally, umbilical cord – anyone in need can request aid from their network of friends. Anyone who’s asked is obliged to help, often by giving livestock, as long as it doesn’t jeopardise their own survival. No one expects a recipient to repay the gift, and no one keeps track of how often a person asks or gives. Osotua runs counter to the way we usually view cooperation, which is all about reciprocity – you scratch my back, I’ll scratch yours. Yet similar forms of generosity turn out to be common in cultures around the world. Some anthropologists think it could represent one of the earliest forms of generosity in human society. That’s not the only curiosity about generosity. In biological and evolutionary terms, it makes no sense to give and get nothing in return. Altruism is rare in other animals, yet humans can be inexplicably kind. Are we generous by nature? How did we get to be this way? What role does culture play in kindness? These are the big questions now being addressed by researchers in the Human Generosity Project, who are using fieldwork, experiments and modelling to explore osotua and other examples of human cooperation. Their aim: to find how best to make the milk of human kindness flow.
8-10-16 Selfish dogs would rather play with a toy than help a human
Selfish dogs would rather play with a toy than help a human
Friend in need, friend indeed. The old adage might not extend to our best friends, dogs, which may be more focused on that bone on the floor than lending a paw. Man’s best friend? Dogs may be more selfish than their sterling reputation suggests – or perhaps they simply don’t understand our requests for help. Our canine companions are unusually good at communicating with us, outperforming other creatures such as chimpanzees, says Patrizia Piotti at the University of Portsmouth, UK. But how helpful are pooches when they know something that humans don’t? To find out whether dogs will show a person where something they have lost is hidden, Piotti and her advisor, Juliane Kaminski, studied 24 family dogs in the lab. Testing each one individually, the researchers put a toy in one corner of the room, and stashed either a notebook that the dog had seen someone using in another, or a stapler that it hadn’t seen before. This was done in view of the dog. When the notebook user returned and searched for the “lost” notepad, the pooches indicated the dog toy more often than the notebook or stapler. And when the dogs did indicate the location of the other objects, they weren’t any better at pointing out the thing the human cared about – the notebook – than the unimportant stapler.
8-10-16 Whales dive slower and feed less in response to shipping noise
Whales dive slower and feed less in response to shipping noise
The noise from shipping is disrupting natural behaviour of humpback whales and could lead to a long term decline in their numbers. Increased shipping noise is disrupting the foraging behaviour of humpback whales in the North Atlantic, and this could result in lower numbers of the whales in the long term. Many whales are found in coastal areas with high levels of shipping traffic that mean there are frequent fatalities from collisions. A team of scientists from the UK and US collected data from 10 whales within the Stellwagen Bank National Marine Sanctuary, a popular whale watching site between Cape Cod and Cape Ann in the US. They used archival tags that simultaneously recorded underwater movements and the acoustic environment to collect the data. They found “significant” effects on foraging, including slower descent rates and fewer side-roll feeding events per dive with increasing ship noise. Previous studies have shown the noise pollution has been shown to alter acoustic communications, distribution patterns and stress responses in a wide range of animals. “These findings indicate that humpback whales on Stellwagen Bank, an area with chronically elevated levels of shipping traffic, significantly change foraging activity when exposed to high levels of ship noise,” the researchers said.
8-10-16 Piltdown review points decisive finger at forger Dawson
Piltdown review points decisive finger at forger Dawson
Researchers have finished an eight-year study of one of the most infamous forgeries in the history of science - the fake human ancestor Piltdown Man. They conclude that the forged fossils were made by one man: the prime suspect and "discoverer" Charles Dawson. The human-like skull fragments and an ape-like jaw, complete with two teeth, shook the scientific world in 1912 but were exposed as a hoax in 1953. New tests show the bones came from two or three humans and one orangutan.
8-9-16 Notorious ‘ape-man’ fossil hoax pinned on one wrongdoer
Notorious ‘ape-man’ fossil hoax pinned on one wrongdoer
New Piltdown Man probe rules out coconspirators in famous anthropological fraud. Human skull fragments from the 20th century fossil fraud known as Piltdown Man contain clues to forgery methods used by one man to trick the anthropological establishment, a new study finds. New investigations of England’s infamously fraudulent Piltdown Man fossils reveal a mix of clever and clumsy methods used by one man to fool early 20th century scientists for 40 years. Lawyer and amateur archaeologist Charles Dawson modified orangutan and human bones to resemble what scientists of the time anticipated a “missing link” between apes and humans would look like, say paleoanthropologist Isabelle De Groote of Liverpool John Moores University in England and colleagues. Dawson and British paleontologist Arthur Smith Woodward announced the discovery of what they called Eoanthropus dawsoni, or Dawson’s dawn man, in December 1912.
8-9-16 Action needed to 'future-proof' pollinators
Action needed to 'future-proof' pollinators
International scientists are calling for action to "future-proof" the prosperity of pollinating insects, birds and mammals. They say agricultural expansion, new pesticides and emerging viruses present the biggest risks in coming decades. And the bats that pollinate plants in tropical and desert climates need legal protection, they report in PeerJ. Some 35% of global crop production and more than 85% of wild flowering plants rely to some degree on pollination. The research took a horizon-scanning approach to identify future issues of concern over the next three decades.
8-9-16 Aging-related protein may play role in depression
Aging-related protein may play role in depression
SIRT1 study in mice suggests possible new treatment target. A busy protein known for its role in aging may also have a hand in depression, a study on mice hints. Under certain circumstances, the aging-related SIRT1 protein seems to make mice despondent, scientists report August 10 in the Journal of Neuroscience. The results are preliminary, but they might ultimately help find new depression treatments. Today’s treatments aren’t always effective, and new approaches are sorely needed. “This is one potential new avenue,” says study coauthor Deveroux Ferguson of the University of Arizona College of Medicine in Phoenix.
8-9-16 T. rex look-alike unearthed in Patagonia
T. rex look-alike unearthed in Patagonia
Though not a close relative, Gualicho shared those puny arms. A newly discovered dinosaur species had a T. rex’s stubby arms, and probably relied on a huge head with a mouthful of teeth for hunting. What had two puny arms, lived 90 million years ago and probably chowed down on other dinosaurs? (Hint: It’s not T. rex.) A new dinosaur discovered in what is now Patagonia had the runty forelimbs of a Tyrannosaurus rex but is no cousin of the giant iconic predator, researchers report July 13 in PLOS ONE.
8-9-16 Dog sperm quality decline is blamed on pet food chemicals
Dog sperm quality decline is blamed on pet food chemicals
Sperm quality in dogs is falling rapidly, a trend now linked to environmental pollutants, which could help explain the purported decline in human fertility. Sperm quality in dogs has fallen rapidly over the past three decades, a trend which could help explain the purported decline in human fertility. The finding has highlighted a potential link between environmental contaminants and fertility – after scientists discovered chemicals which had a detrimental effect on sperm function in some commercially available pet foods. Researchers at the University of Nottingham believe that the study could help explain the reported significant decline in human semen quality.
8-8-16 Ice age fashion showdown: Neanderthal capes versus human hoodies
Ice age fashion showdown: Neanderthal capes versus human hoodies
Animal remains at ancient hominin sites suggest that Neanderthals didn't dress to impress, whereas early modern humans had more sophisticated tastes. Early modern humans dressed for ice age success – Neanderthals, not so much. An analysis of animal remains at prehistoric hominin sites across Europe suggests modern humans clad themselves in snug, fur-trimmed clothing, while Neanderthals probably opted for simple capes. Even so, the finding suggests our extinct cousin was far more sophisticated than once thought. Some researchers argue that Neanderthals didn’t bother with clothes at all, others that they dressed in much the same way as early members of our species. Mark Collard at Simon Fraser University in Burnaby, Canada, and his colleagues think the truth lies somewhere in between.
8-8-16 Some of the earliest plants took root by growing up, not down
Some of the earliest plants took root by growing up, not down
A geological formation in China reveals how a small plant managed to anchor earth to a depth of 15 metres, allowing soils to form. It was one of the first examples of geoengineering: when plants began to colonise the land they stabilised sediments, generated soils and greened the planet. Now we have a window on the process, thanks to a spectacular rock formation in South China, showing some of the oldest known fossils of early root-like systems from 20 million years before the first forests grew. When researchers look at the greening of the primeval continents they tend to focus on the appearance of trees with deep roots that could enhance the weathering of rock and allow thick, rich soils to form. But this was the final part of the process: the first trees grew about 390 million years ago, tens of millions of years after plants first colonised land.
8-9-16 Ancient reptiles saw red before turning red
Ancient reptiles saw red before turning red
Gene in birds, turtles linked to both vision and coloration. A gene shared by western painted turtles and zebra finches points to red color vision, and perhaps red coloration, in dinosaurs. You’ve got to see it to be it. A heightened sense of red color vision arose in ancient reptiles before bright red skin, scales and feathers, a new study suggests. The finding bolsters evidence that dinosaurs probably saw red and perhaps displayed red color. The new finding, published in the Aug. 17 Proceedings of the Royal Society B, rests on the discovery that birds and turtles share a gene used both for red vision and red coloration. More bird and turtle species use the gene, called CYP2J19, for vision than for coloration, however, suggesting that its first job was in sight.
8-5-16 Gene doping in sport could make the Olympics fairer and safer
Gene doping in sport could make the Olympics fairer and safer
Sports authorities say they will soon start testing athletes for genetic enhancements. But gene doping is going to be impossible to detect, and it is counterproductive to outlaw it. Elizabeth Parrish of the anti-ageing company BioViva claims to have given herself two kinds of experimental gene therapy, one of which blocks the breakdown of muscle tissue. In other words, your muscles stay strong even if you don’t exercise – and grow faster if you do. It’s not clear if Parrish really has done this, let alone if it worked. Nonetheless, you can be certain that BioViva is already getting calls from sportspeople desperate to try it themselves. Gene therapists working on treatments that could help athletes say they often get such calls. There have yet to be any confirmed cases of athletes genetically enhancing their bodies. But this could be because none have ever been tested. Sports authorities are certainly taking the prospect seriously. Last week the International Olympic Committee said that samples from athletes competing in Rio will be tested for gene doping. Conventional gene therapy involves adding extra genes, whose sequence differs from a person’s own version of these genes. If you find cells with these extra genes, that athlete has been gene doping.Webmaster's comment: Changing your own genes has got to be your human right. And if you benefit athletically from that, so be it.)
8-5-16 New fossil suggests echolocation evolved early in whales
New fossil suggests echolocation evolved early in whales
Intricate 27-million-year-old inner ear bones show features of high-frequency hearing. The skull of an ancient whale unearthed in South Carolina adds to evidence that the ancestors of modern toothed whales, such as orcas and dolphins, had high-frequency hearing. A roughly 27-million-year-old fossilized skull echoes growing evidence that ancient whales could navigate using high-frequency sound. Discovered over a decade ago in a drainage ditch by an amateur fossil hunter on the South Carolina coast, the skull belongs to an early toothed whale. The fossil is so well-preserved that it includes rare inner ear bones similar to those found in modern whales and dolphins. Inspired by the Latin for “echo hunter,” scientists have now named the ancient whale Echovenator sandersi.
8-5-16 Men may have evolved better 'making up' skills
Men may have evolved better 'making up' skills
Men's historical dominance of the workplace may, in part, be because of their ability to reconcile with enemies after conflict, a new study suggests. Researchers examined the aftermath of same-sex sporting events and found that men spent longer talking, touching or embracing their opponents than women. These efforts to patch things up ensure the males can then co-operate more successfully in the future. The authors believe that this trait has been carried down through the years.
8-5-16 Incredible shrinking Americans
Incredible shrinking Americans
Americans are getting shorter, while in some countries people are experiencing a growth spurt, new research reveals. Since 1914 U.S. men have fallen from third tallest in the world to 37th, with an average height of 5 feet 9 inches; women, once ranked fourth tallest globally, now place 42nd, at 5 feet 4 inches. Researchers combined the results of 1,472 studies that measured the heights of 18.6 million people from 200 countries. Though Americans have grown 2 inches over the century, they’ve actually shrunk slightly in the past two decades. Meanwhile, Dutch men and Latvian women have climbed to the top of the charts, while South Korean women and Iranian men have grown at the fastest rate. Americans can blame their stagnant growth on genetics, but also on a penchant for processed foods high in sugar and saturated fat but devoid of many essential nutrients. “There was a time when the U.S. was the land of plenty,” researcher Majid Ezzati of Imperial College London tells NPR.com. “But increasingly over time, the quality of nutrition has worsened.”
8-5-16 Alcohol may cause cancer
Alcohol may cause cancer
A daily glass of red wine may lower heart disease risk, but new research presents stronger evidence that alcohol is a direct cause of at least seven forms of cancer. “Promotion of health benefits from drinking at moderate levels is seen increasingly as disingenuous or irrelevant in comparison to the increase in risk of a range of cancers,” says study author Jennie Connor of New Zealand’s University of Otago. An analysis of recent research found that alcohol might cause cancers of the mouth and throat, larynx, esophagus, liver, colon, bowel, and breast. The more people drink, the worse the odds, reports HuffingtonPost.com. Even small amounts of alcohol aren’t risk-free, the analysis reveals. Exactly how alcohol causes cancer remains unclear. Researchers suspect a compound called acetaldehyde, which forms when alcohol is digested, might damage cellular DNA. Alcohol could also increase the body’s vulnerability to carcinogens and raise estrogen levels in women, increasing their risk for breast cancer.
8-5-16 Rats offer clues to biology of alcoholism
Rats offer clues to biology of alcoholism
Hundreds of genes involved in drinking preferences, study finds. A study of rats that drink heavily reveals that hundreds of genes may be involved in alcoholism. Alcoholism may stem from using genes incorrectly, a study of hard-drinking rats suggests. Rats bred either to drink heavily or to shun alcohol have revealed 930 genes linked to a preference for drinking alcohol, researchers in Indiana report August 4 in PLOS Genetics. Human genetic studies have not found most of the genetic variants that put people at risk for alcoholism, says Michael Miles, a neurogenomicist at Virginia Commonwealth University in Richmond. The new study takes a “significant and somewhat novel approach” to find the genetic differences that separate those who will become addicted to alcohol from those who drink in moderation.
8-5-16 Internal clock helps young sunflowers follow the sun
Internal clock helps young sunflowers follow the sun
Circadian strategy offers advantages, study finds. Mature sunflowers aim their flower heads to the east. That way, the flowers get warmer and attract more pollinators. Young sunflowers grow better when they track the sun’s daily motion from east to west across the sky. An internal clock helps control the behavior, biologist Stacey Harmer and colleagues report in the Aug. 5 Science. Depending on the time of day, certain growth genes appear to be activated to different degrees on opposing sides of young sunflowers’ stems. The east side of their stems grow faster during the day, causing the stems to gradually bend from east to west. The west side grows faster at night, reorienting the plants to prepare them for the next morning. “At dawn, they’re already facing east again,” says Harmer, of the University of California, Davis. The behavior helped sunflowers grow bigger, her team found. (Webmaster's comment: Evolution helps again.)
8-5-16 A map of the human brain
A map of the human brain
Neuroscientists have been forced to rely on a relatively rough diagram of the human brain to perform delicate surgeries or research treatments for debilitating disorders like Alzheimer’s disease and schizophrenia. But a new map created at Washington University in St. Louis is being hailed as a milestone, providing the most detailed picture yet of the cerebral cortex—the brain’s outermost layer involved in language, consciousness, and problem solving. The brilliantly colored image reveals 180 distinct areas within this wrinkled mass of gray matter, including 97 that were previously unknown, CNN.com reports. The map was created using MRI scans of 210 healthy adult brains at rest and brains performing simple tasks. Researchers drew lines around specific regions of the cerebral cortex based on their structure, function, and connectivity with other parts of the brain. The map provides neuroscientists with a “typical” brain template that could shed light on how the mind is affected by disorders like dementia, autism, and epilepsy. “You know what maps of the world looked like in 1500 and you know what they looked like in 1950?” asks National Institute of Mental Health’s Dr. Greg Farber. “I think, in terms of resolution and quality, we moved from 1500 to 1950.”
8-5-16 An undersea vent: Life’s incubator?
An undersea vent: Life’s incubator?
How and where life arose out of inanimate matter is a mystery that has long consumed evolutionary biologists. Charles Darwin famously speculated that the first living things arose in some “warm little pond.” But a new genetic study suggests life first formed in a far less hospitable environment: scalding deep-sea hydrothermal vents—gas-filled plumes created by the interaction of seawater and magma erupting through the ocean floor. Biologists at Heinrich Heine University in Germany arrived at that conclusion after creating a detailed genetic profile of a 4 billion–year-old organism dubbed Luca, an acronym for the Last Universal Common Ancestor. The researchers examined 6.1 million protein-coding genes found in bacteria and archaea—single-celled organisms with no nucleus (prokaryotes) that eventually gave rise to all plants and animals (eukaryotes), The New York Times reports. After arranging the genes in evolutionary family trees, they found that 355 likely originated from Luca. The genetic reconstruction suggests Luca thrived in an intensely hot setting devoid of oxygen and relied on hydrogen and metals for energy, precisely the conditions in deep-sea vents. “I was flabbergasted at the result—I couldn’t believe it,” says study leader William Martin. His research doesn’t confirm that life began in the vents: Some biologists believe the first organisms started out on land, but may have been propelled undersea 4 billion years ago, after a shower of asteroids and comets reshaped the planet.
8-4-16 Counting genetic mutations predicts how soon you’ll get cancer
Counting genetic mutations predicts how soon you’ll get cancer
Analysing mutations in genes only weakly linked with sarcoma, a cancer that often targets young people, can indicate how early the disease may strike. How young will you be when you get cancer? The number of mutations you have in different genes can bring that date closer. We already know that mutations in cancer genes like BRCA1 and BRCA2 increase cancer risk. But now David Thomas at the Garvan Institute of Medical Research in Sydney and his colleagues have shown for the first time that mutations in genes associated with a lower cancer risk can little by little add up to an even deadlier effect. The team compared the genetic profiles of healthy individuals with those of 1162 people with sarcomas – cancers that develop in bones and soft tissue and disproportionately affect young people. In particular, they focused on 72 genes – some strongly linked to sarcoma, like the TP53 gene, and others that are only weakly linked. As they expected, a mutation in the TP53 gene increased a person’s sarcoma risk – half developed cancer by the age of 32. But people with mutations in two genes only weakly associated with sarcoma developed tumours at a younger age – half had cancer by the age of 25. This effect was even stronger in those who had three or more mutations in such genes.
8-4-16 Baby monkeys smile in their sleep – more so than human babies
Baby monkeys smile in their sleep – more so than human babies
Videos of sleeping baby Japanese macaques show they smile much more than human babies. Are they having sweeter dreams? Baby Japanese macaques smile more while they sleep than any other species – far more than human babies or infant chimpanzees. Baby humans and chimps were the only species known to smile in their sleep. Now Fumito Kawakami at Kyoto University in Japan, and his colleagues are looking for others. The researchers filmed seven snoozing Japanese macaques aged between 4 and 21 days and recorded how often they smiled during rapid eye movement (REM) sleep, which is associated with dream states, and non-REM sleep. The baby macaques smiled 41 times an hour in REM sleep, and not at all in non-REM sleep. In comparison, human babies smile twice per hour, while dozing infant chimpanzees smile just once in 5 hours in REM sleep. “We are not sure what is triggering this smiling in their brains,” says Kawakami.
8-4-16 Mystery of why some sunflowers track the sun across skies solved
Mystery of why some sunflowers track the sun across skies solved
An internal clock helps young sunflowers track the sun’s movement to boost their growth – while mature plants face the dawn to lure in more pollinators. The heads of young sunflower plants — those with immature flowers — follow the sun during the day, then reverse course at night, so they’re ready to face the dawn. But no one knew how much of an advantage the plants were gaining from their daily dance, says Stacey Harmer at the University of California in Davis. To find out, Harmer and her colleagues tethered some plants so they couldn’t move, and rotated the pots of others so they were facing the wrong way in the morning, away from the sunrise. They found that leaves of both groups of sunflowers were about 10 per cent smaller than leaves from plants that were allowed to follow the sun. “They’re less efficient if they can’t track,” says Harmer.
8-4-16 Do Amish hold clue to preventing asthma in children?
Do Amish hold clue to preventing asthma in children?
The Amish community in the US has long been famous for shunning modern technology and preserving traditional ways of life, using horses for farming and for transport. Now it appears that their closer contact with animals could have an unexpected benefit - preventing asthma in children. A new study from the US compared the Amish with a similar community, the Hutterites, who use more modern farming methods. Both groups have similar genetic ancestry and follow similar diets, but researchers found that childhood asthma rates differed strongly. About 5% of Amish schoolchildren tested in the study had asthma compared with 21.3% of the Hutterite children. The study in the New England Journal of Medicine suggested that children's immune systems in the Amish community were being bolstered by house dust that contained more microbes from farm animals.
8-4-16 Brain's thirst circuit 'monitors the mouth'
Brain's thirst circuit 'monitors the mouth'
Low temperatures apparently shut down the same neurons that generate thirst. Scientists have glimpsed activity deep in the mouse brain which can explain why we get thirsty when we eat, and why cold water is more thirst-quenching. A specific "thirst circuit" was rapidly activated by food and quietened by cooling down the animals' mouths. The same brain cells were already known to stimulate drinking, for example when dehydration concentrates the blood. But the new findings describe a much faster response, which predicts the body's future demand for water. The researchers went looking for this type of system because they were puzzled by the fact that drinking behaviour, in humans as well as animals, seems to be regulated very quickly.
8-4-16 Being fat in middle age may shrink your brain’s white matter
Being fat in middle age may shrink your brain’s white matter
People who are overweight have less white matter in their brains, making them look a decade older – an effect that doesn’t seem to kick in until middle age. The brains of overweight middle-aged people resemble brains that are a decade older in healthier people. A study of 473 adults has found that people who are overweight have less white matter, which connects different brain areas and enables signaling between them. The volume of white matter in the brains of overweight people at 50 were similar to that seen in the brains of lean people at 60. Human brains naturally shrink with age, but previous research has shown that this seems to happen more quickly in obese people. “As our brains age, they naturally shrink in size, but it isn’t clear why people who are overweight have a greater reduction in the amount of white matter,” says Lisa Ronan, at the University of Cambridge, a member of the research team. “We can only speculate on whether obesity might in some way cause these changes or whether obesity is a consequence of brain changes.”
8-3-16 First evidence birds nap in flight without dropping out of sky
First evidence birds nap in flight without dropping out of sky
Brain recorders fitted to 14 great frigatebirds show these birds sleep on the wing, usually while circling in rising air currents. The debate has finally been put to bed. Wearable brainwave recorders confirm that birds do indeed sleep while flying, but only for brief periods and usually with one half of their brain. We know several bird species can travel vast distances non-stop, prompting speculation that they must nap mid-flight. Great frigatebirds, for example, can fly continuously for up to two months. On the other hand, the male sandpiper, for one, can largely forgo sleep during the breeding season, hinting that it may also be possible for birds to stay awake during prolonged trips. To settle this question, Niels Rattenborg at the Max Planck Institute for Ornithology in Seewiesen, Germany, and his colleagues fitted small brain activity monitors and movement trackers to 14 great frigatebirds. During long flights, the birds slept for an average of 41 minutes per day, in short episodes of about 12 seconds each. By contrast, they slept for more than 12 hours per day on land. Frigatebirds in flight tend to use one hemisphere at a time to sleep, as do ducks and dolphins, but sometimes they used both. “Some people thought that all their sleep would have to be unihemispheric otherwise they would drop from the sky,” says Rattenborg. “But that’s not the case – they can sleep with both hemispheres and they just continue soaring.” Sleep typically took place as the birds were circling in rising air currents, when they did not need to flap their wings.
8-3-16 Smart mice have better odds of survival
Smart mice have better odds of survival
African striped mice must brave dry summers to mate. Certain cognitive skills may enhance their chances of making it through the drought, a new study finds. Pinky and The Brain's smarts might not be so far-fetched. Some mice are quicker on the uptake than others. While it might not lead to world domination, wits have their upside: a better shot at staying alive. Biologists Audrey Maille and Carsten Schradin of the University of Strasbourg in France tested reaction time and spatial memory in 90 African striped mice (Rhabdomys pumilio) over the course of a summer. For this particular wild rodent, surviving harsh summer droughts means making it to mating season in the early fall. The team saw some overall trends: Females were more likely to survive if they had quick reflexes, and males were more likely to survive if they had good spatial memory. Cognitive traits like reacting quickly and remembering the best places to hide are key to eluding predators during these tough times but may come with trade-offs for males and females. The results show that an individual mouse’s cognitive strengths are linked to its survival odds, suggesting that the pressure to survive can shape basic cognition, Maille and Schradin write August 3 in Biology Letters.
8-3-16 Found: brain switches that wake flies up and send them to sleep
Found: brain switches that wake flies up and send them to sleep
Activating specific neurons in fruit fly brains sends them straight to sleep, or rouses them from slumber – and we may have a similar switch. Neuronal switches have been discovered that can suddenly rouse flies from slumber – or send them into a doze. There are several parallels between sleep in flies and mammals, making fruit flies a good choice for investigating how we sleep. One way to do this is to use optogenetics to activate specific neurons to see what they do. This works by using light to turn on cells genetically modified to respond to certain wavelengths. Gero Miesenböck at the University of Oxford and his team have discovered how to wake flies up. Using light as the trigger the team stimulated neurons that release a molecule called dopamine. The dopamine then switched off sleep-promoting neurons in what’s called the dorsal fan-shaped body, waking the flies. Meanwhile, Fang Guo at Brandeis University in Waltham, Massachusetts, and his team have found that activating neurons that form part of a fly’s internal clock will send it to sleep. When stimulated, these neurons released glutamate, which turned off activity-promoting neurons in the master pacemaker area of the brain.
8-3-16 Videos reveal the Russian doll parasitic world of the deep seas
Videos reveal the Russian doll parasitic world of the deep seas
Footage from the ocean depths shows the wealth of parasites hitching rides on fish - and yet others hitching rides on them. Deep below the ocean’s surface, parasitic crustaceans are latching on to fish that eke out a living. Video from the ocean depths has revealed their diversity and range for the first time. Parasites may be an indicator of a healthy ecosystem, as they can regulate animal populations and keep them from growing out of control, says Andrea Quattrini at Harvey Mudd College in Claremont, California. “And yet virtually nothing is known about their importance in the deep sea,” she says. “The first step is really just to document their diversity, and how many and what species are being infected.” Quattrini and Amanda Demopoulos at the US Geological Survey studied films collected by a remotely operated underwater vehicle (ROV) surveying the sea floor off the coast of the north-eastern US. One third of the fish species spotted during 43 separate ROV dives – and up to half of fish of some species – had up to several dozen visible parasites: isopods and copepods. Some of these have hooks on the ends of their legs that they embed into the fish. Others bury their head into the flesh. One parasitic copepod even had parasites of its own: eight leeches clung to it.
8-3-16 First diagnosis of dinosaur arthritis shows it lived in pain
First diagnosis of dinosaur arthritis shows it lived in pain
The 70 million year old dinosaur must have lived in pain as it had septic arthritis, an especially nasty form of the disease caused by infection. A dinosaur has been diagnosed with severe arthritis 70 million years after its death. Scientists believe the hadrosaur, a plant-eating duck-billed dinosaur, must have endured considerable suffering before reaching the end of its life. X-ray analysis of its fossilised elbow joint revealed evidence of septic arthritis, an especially nasty form of the disease caused by infection and known to afflict modern birds, crocodiles and humans. A micro-tomography scan — a high resolution version of the kind of CT scans used in hospitals — showed that the joint was fused and covered in bony growths. It is the first time septic arthritis has been seen in a dinosaur, although another arthritic condition called osteomyelitis was quite common among the creatures. In this case, osteomyelitis was ruled out because of the “highly reactive” bone growth and the location of the affected area around the elbow joint.
8-2-16 Our strange lack of fur may be key to our success
Our strange lack of fur may be key to our success
Our strange lack of fur may be key to our success. It might not seem strange, because we are used to having relatively little hair covering our bodies. But when we compare ourselves to the rest of the mammals, and our closest living ape cousins, it is downright bizarre that we are the only large-bodied mammal with so little of it. Unlike hairy chimpanzees and bonobos – and all other primates – most of our skin is on display. We have evolved this way, even though fur is beneficial: it insulates and protects the skin, and in some cases acts as a useful camouflage. So if it is so advantageous, why did we lose so much of it? It was Charles Darwin who first taught the public that humans are descended from an ape-like ancestor. He also wondered why we had so little hair. Something must have created an evolutionary pressure for these hominins to lose their fur"No one supposes that the nakedness of the skin is any direct advantage to man; his body, therefore, cannot have been divested of hair through natural selection," Darwin wrote in The Descent of Man. He proposed that we lost much of our fur due to sexual selection: we preferred hairless mates, and that is why hairlessness became common. But that cannot be the whole picture. Before a preference for hairlessness began, we first had to start losing hair. Our earliest human-like ancestors, known as hominins, were ape-like. For them, fur would have been useful, keeping them warm on cold nights. Something must have created an evolutionary pressure for these hominins to lose their fur.
8-2-16 Tolerance of smoke may have given us an edge over Neanderthals
Tolerance of smoke may have given us an edge over Neanderthals
Modern humans carry a mutation that allows us to deal with health effects of smoke inhalation – something our Neanderthal relatives seem to have lacked. Where there’s fire there’s often smoke – which might have been bad news for Neanderthals and other ancient hominins. Modern humans carry a genetic mutation that reduces our sensitivity to cancer-causing chemicals found in wood smoke. But Neanderthals and Denisovans apparently lacked the mutation. Harnessing fire was one of the key events in hominin prehistory. Fire offered light, warmth, better protection from predators and the possibility of easier-to-digest cooked food. But smoke is something to be wary of. “Even today, smoke inhalation increases susceptibility to lung infections,” says Gary Perdew at Pennsylvania State University. It might have been a significant problem during the Stone Age, given that hominins often lighted fires in caves or other enclosed areas. “If you were in a cave trying to cook, the amount of smoke you’d breathe in would be ridiculous,” says Perdew. Our species, Homo sapiens, might have been particularly well suited to those conditions, though. Perdew and his colleagues looked at the genomes of three Neanderthals and a Denisovan, and compared them with genomes from living people and one member of our species who lived 45,000 years ago. The researchers found that this ancient member of our species already carried a mutation not seen in either Neanderthals or Denisovans. It occurs in the AHR gene, which produces a receptor that helps regulate our response to carcinogenic polycyclic aromatic hydrocarbons often found in wood smoke.
8-2-16 Running doesn’t make rats forgetful
Running doesn’t make rats forgetful
Earlier studies on other rodents linked workout-induced birth of new brain cells with memory loss. Four weeks of exercise on a running wheel didn’t erase memories in rats, contrary to a phenomenon that has been observed previously in other rodent species. Exercise may not erase old memories, as some studies in animals have previously suggested. Running on an exercise wheel doesn’t make rats forgetprevious trips through an underwater maze, Ashok Shetty and colleagues report August 2 in the Journal of Neuroscience. Exercise or not, four weeks after learning how to find a hidden platform, rats seem to remember the location just fine, the team found. The results conflict with two earlier papers that show that running triggers memory loss in some rodents by boosting the birth of new brain cells. Making new brain cells rejiggers memory circuits, and that can make it hard for animals to remember what they’ve learned, says Paul Frankland, a neuroscientist at the Hospital for Sick Children in Toronto. He has reported this phenomenon in mice, guinea pigs and degus.
8-2-16 Oldest evidence of cancer in human family tree found
Oldest evidence of cancer in human family tree found
Abnormal growth in a 1.6-million- to 1.8-million-year-old toe bone was malignant tumor. A 1.6-million- to 1.8-million-year-old toe bone sports a large, bony growth that represents the earliest known case of a potentially fatal cancer in the human evolutionary family, researchers say. Cancer goes way, way back. A deadly form of this disease and a noncancerous but still serious tumor afflicted members of the human evolutionary family nearly 2 million years ago, two new investigations of fossils suggest. If those conclusions hold up, cancers are not just products of modern societies, as some researchers have proposed. “Our studies show that cancers and tumors occurred in our ancient relatives millions of years before modern industrial societies existed,” says medical anthropologist Edward Odes of the University of the Witwatersrand in Johannesburg, a coauthor of both new studies. Today, however, pesticides, longer life spans and other features of the industrialized world may increase rates of cancers and tumors.
8-2-16 How genomics is dramatically changing the future of medicine
How genomics is dramatically changing the future of medicine
This new field is producing some of the most personalized and effective medical treatments in human history. As the World Health Organization defines it, genomics is the study of genes and how they function. When applied to medicine, genomics is being used to identify how our genes relate to human development. That includes "every genetic element that has an impact on disease, your health, longevity, and even behavior," says Dr. Edison Liu, an oncologist and the CEO of The Jackson Laboratory for Genomic Medicine. "Genomics provides the personalized blueprint of your entire genetic make-up." In other words, this emerging field is providing some of the most personalized and effective medical treatments in human history.
8-2-16 Last woolly mammoths 'died of thirst'
Last woolly mammoths 'died of thirst'
One of the last known groups of woolly mammoths died out because of a lack of drinking water, scientists believe. The Ice Age beasts were living on a remote island off the coast of Alaska, and scientists have dated their demise to about 5,600 years ago. They believe that a warming climate caused lakes to become shallower, leaving the animals unable to quench their thirst. Most of the world's woolly mammoths had died out by about 10,500 years ago. Scientists believe that human hunting and environmental changes played a role in their extinction. But the group living on St Paul Island, which is located in the Bering Sea, managed to cling on for another 5,000 years.
8-1-16 Woolly mammoths’ last request: Got water?
Woolly mammoths’ last request: Got water?
Isolated island population went extinct 5,600 years ago when lakes dried up. Woolly mammoths on an isolated Alaskan island probably died out when the lakes on the island dried up, researchers report. Thirst drove one of the last populations of woolly mammoths to extinction. A small group of holdouts on an isolated Alaskan island managed to last about 8,000 years longer than most of their mainland-dwelling brethren. But by about 5,600 years ago, the island’s lakes — the only source of freshwater — became too small to support the mammoths, scientists report online the week of August 1 in the Proceedings of the National Academy of Sciences.
8-1-16 America’s last mammoths died of thirst on an Alaskan island
America’s last mammoths died of thirst on an Alaskan island
Three kinds of data all agree that 5600 years ago, one of the last mammoth populations went extinct when climate change dried up their lakes. Long after most of their kind had died out, one group of woolly mammoths was still surviving on an Alaskan island. Now it’s clear why they finally bit the dust: a warming climate caused their lakes to dry up. Mammoths were in crisis at the end of the last ice age, when human hunters were able to spread into their habitat in the northern hemisphere. Most mammoths on mainland Asia and North America went extinct over 13,000 years ago, either due to climate change, hunting or a mix of both. But a few hardy mammoth herds clung to islands in the Arctic devoid of humans for several millennia. One of these populations retreated to the Bering land bridge between Siberia and North America. As the ocean rose, the mammoths became stranded on the small, low Alaskan island now called St Paul. What happened to them remained a mystery until Russell Graham at Pennsylvania State University and colleagues pinpointed both the time and cause of their extinction: 5600 years ago, they ran out of water.
8-1-16 Mysterious dark brain cells linked to Alzheimer’s and stress
Mysterious dark brain cells linked to Alzheimer’s and stress
Dark and shrunken microglia cells identified in the brains of people and mice seem to smother brain connections and are associated with age and disease. Mysterious shrunken cells have been spotted in the human brain for the first time, and appear to be associated with Alzheimer’s disease. “We don’t know yet if they’re a cause or consequence,” says Marie-Ève Tremblay of Laval University in Québec, Canada, who presented her discovery at the Translational Neuroimmunology conference in Big Sky, Montana, last week. The cells appear to be withered forms of microglia – the cells that keep the brain tidy and free of infection, normally by pruning unwanted brain connections or destroying abnormal and infected brain cells. But the cells discovered by Tremblay appear much darker when viewed using an electron microscope, and they seem to be more destructive. “It took a long time for us to identify them,” says Tremblay, who adds that these shrunken microglia do not show up with the same staining chemicals that normally make microglia visible under the microscope.
8-1-16 The Pandora Effect: Why curiosity usually beats common sense
The Pandora Effect: Why curiosity usually beats common sense
Research shows that we just can’t help ourselves and find it hard to curb our curiosity – even when it’s better that we do.Curiosity is often a positive thing: it is at the heart of scientific progress, for example. But it also has a negative side. “Rubbernecking” – gawping at car crashes when we drive past – is one such example. A government-sponsored study of accidents on the M6 motorway attributed 29 per cent of them during the study period to drivers rubbernecking in the opposite carriageway. The issue was eventually tackled by the UK Highways Agency, who reduced accidents by erecting giant screens at crash sites. The problem is we just can’t help ourselves. In a recent study, researchers have found that we’re still curious even if we know the outcome will be negative. Christopher Hsee of the University of Chicago and colleagues dubbed the tendency to opt for an uncertain outcome even when we know it might have unpleasant consequences, the Pandora Effect.
8-1-16 How I learned to stop worrying and love germs
How I learned to stop worrying and love germs
Because Ed Yong's eye-opening I Contain Multitudes, out Aug. 9 from Ecco, offers reassurance that these living organisms are, more likely than not, your friends. Yong's book is an admiring and thoroughly researched study of the microbial world: the "microscopic menagerie" of bacteria, fungi, archaea, and viruses that live, essentially, everywhere. Yong, however, focuses on their relationship with animals, and especially humans. Each of us is inhabited by a distinct set, or microbiome, whose denizens are influenced by the genes we inherit, the places we live, the people we encounter, the food we eat, and the drugs we've taken. The microbes in our bellies differ from the ones under our arms. The latest estimates suggest we each carry 39 trillion of them.
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