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40 Evolution News Articles
for September 2021
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Nature cares only that you reproduce and raise the kids.
After you've done that, get out of the way.

9-22-21 Covid: Immune therapy from llamas shows promise
A Covid therapy derived from a llama named Fifi has shown "significant potential" in early trials. It is a treatment made of "nanobodies", small, simpler versions of antibodies, which llamas and camels produce naturally in response to infection. Once the therapy has been tested in humans, scientists say, it could be given as a simple nasal spray - to treat and even prevent early infection. Prof James Naismith described nanobodies as "fantastically exciting". Prof Naismith, who is one of the lead researchers and director of the Rosalind Franklin Institute in Oxfordshire, explained that coronavirus-infected rodents treated with the new nanobody nasal spray fully recovered within six days. The treatment has, so far, been tested only in those lab animals, but Public Health England said it was among the "most effective SARS-CoV-2 neutralising agents" it had ever tested. This apparent covid-fighting potency comes from the strength with which nanobodies bind to the virus. Just like our own antibodies, virus-specific nanobodies latch on to and bind to viruses and bacteria that invade our bodies. This binding essentially tags an invading virus with an immune "red flag", to allow the rest of the body's immune armoury to target it for destruction. The nanobodies that these researchers produced - with the help of a llama's immune system - bind particularly tightly. "That's where we had some help from Fifi the 'Franklin [Institute] llama'," explained Prof Naismith. By vaccinating Fifi with a tiny, non-infectious piece of the viral protein, the scientists stimulated her immune system to make the special molecules. The scientists then carefully picked out and purified the most potent nanobodies in a sample of Fifi's blood; those that matched the viral protein most closely, like the key that best fits a specific lock. The team was then able to grow large quantities of the specially selected, most potent molecules.

9-22-21 Why only some people may get COVID-19 booster shots at first
Experts want more data before making the jabs more widespread. In the United States, it’s looking like booster shots of Pfizer-BioNTech’s COVID-19 vaccine won’t be widely available to the general public starting this week. A panel of expert advisers to the U.S. Food and Drug Administration unanimously recommended September 17 that boosters next be allowed for only certain groups: people 65 years and older, individuals at high risk of severe COVID-19 and those with jobs that put them at high risk of exposure. That’s more limited in scope than what the Biden administration proposed in August. Officials had announced plans to offer a third dose of Pfizer-BioNTech’s vaccine to the general public at least six months after vaccination starting September 20, pending an OK from the FDA. Since officials unveiled that plan, it’s been widely debated. Some researchers — including Pfizer scientists — argue that because the vaccine’s protection against infections is waning, that could foreshadow a possible dip in protection against severe disease too. So the time to bolster everyone’s protection with a third dose is now, these researchers say. But others disagree, contending that it’s more important to focus on getting doses to unvaccinated people first, and that many younger, healthy vaccinated people remain well-protected against severe disease and death after just two doses. Third doses are already authorized for moderately to severely immunocompromised people who may not develop good protection from the initial shots (SN: 7/23/21). The case for another dose was obvious for that group, says Mark Slifka, a viral immunologist at Oregon Health & Science University in Portland who wasn’t involved with the FDA panel. The data were “clear as day that the third dose was important” and could help boost the levels of protective antibodies in some patients.

9-21-21 We can now bioengineer catnip instead of extracting it from plants
The key ingredient in catnip, called nepetalactone, can now be brewed in genetically engineered yeast. The chemical is a highly effective insect repellent, but catnip plants (Nepeta cataria) don’t contain enough of it to make production from these commercially viable. Insect repellents can help prevent serious diseases such as malaria, as well as nuisance bites. DEET is the most widely used mosquito repellent worldwide and is often still the most effective. However, some mosquito populations are evolving resistance to DEET, so alternatives are needed. Many studies have shown that nepetalactone is an effective insect repellent, with some even finding it more effective than DEET. Yet while catnip in various forms has long been used as a repellent, mass production of a cheap version isn’t feasible using the plant. Instead, Vincent Martin and his colleagues at Concordia University in Canada added eight extra genes to a strain of yeast, including some key enzymes from catnip, to create a chemical pathway for nepetalactone production. “We still need to do some work to boost levels,” says Martin. “I don’t believe it will be a huge hurdle.” The main obstacle is that the process also produces a substance toxic to the yeast. However, other groups engineering yeasts to produce various chemicals have had the same problem, and have solved it, Martin says. The researchers are now in discussion with companies about getting the investment needed to develop the yeast further and commercialise the process. They will also need to look at whether nepetalactone acts as a cat attractant as well as an insect repellent. “If you are walking around with this molecule on you, will there be no mosquitoes, but all the neighbourhood cats chasing you around? To be honest, I don’t know,” says Martin. “That’s certainly something we’re going to have to investigate.”

9-20-21 Stroke rehab should be offered for months longer than it currently is
People who have experienced a stroke may benefit from being treated with physiotherapy for much longer than is typically the case, to take best advantage of a critical window for rehabilitation exercises. Strokes involve damage to brain tissue caused by a blood clot or a burst blood vessel, which can leave people unable to use an arm or leg, for instance. People generally do recover some function as time passes, especially with physiotherapy. This is thought to be because the brain forms new neural pathways to replace the ones lost, an example of a rewiring process called neuroplasticity. To investigate the benefits of physio, Elissa Newport at Georgetown University Medical Center in Washington DC and her colleagues studied the effects of giving an extra 20 hours of treatment, on top of usual rehab, to 72 people who had a stroke that affected an arm. Each participant was randomly assigned to receive up to 3 hours of physiotherapy a day, either in the first month after the stroke, between months two and three, after six months or not at all. After one year, people who got the extra therapy between months two and three improved the most, by nearly seven points on a commonly used 57-point scale for rating physical ability, compared with usual care. That could mean the difference between being able to dress independently and not, says Newport. People who got the extra therapy in the first month improved by about five points, and people who got it after six months showed no significant benefit. The difference between treatment in the first month and from months two to three wasn’t statistically significant. But the fact that benefits were seen during the third month contradicts the prevailing belief that for post-stroke rehab, “the earlier the better”, says Newport. In the US, most stroke survivors get rehab only for the first four weeks, while in the UK it tends to last up to six weeks.

9-17-21 Woman who first gained sense of smell at age 24 finds it disturbing
A woman who was born without the brain regions required for smell has mysteriously started smelling things for the first time in her twenties and finds it highly unpleasant. The woman was diagnosed with congenital anosmia – the inability to smell – when she was 13. Brain imaging revealed she was missing the olfactory bulbs in her forebrain that detect odour information from the nose and transmit it to other parts of the brain involved in smell perception. Then, when she was 24, she had an unexpected smell awakening. She suddenly began noticing scents like lavender, garlic and manure, with a new smell experience occurring every few weeks. The woman reported feeling disturbed by her new sense, and the fact that she disliked almost all the new smells she encountered increased her anxiety. On one occasion, she felt so overwhelmed she fainted. A group of smell specialists at the University of Dresden Medical School in Germany conducted tests to try to understand how she had learned to smell. They presented her with 32 scents and found she could smell half of them. She could detect orange, mint, smoke, turpentine, ginger and lilac, for example, but not coconut, banana, leather, liquorice or cocoa. “It’s not like she only smells food-related things or bad odours, it’s all over the place,” says Thomas Hummel at the University of Dresden Medical School, one of her specialists. Next, they monitored her brain activity when she sniffed rotten egg gas and rose perfume using electroencephalography (EEG). This confirmed that her brain was responding to the odours. But brain imaging showed she still had no olfactory bulbs, leaving her medical team puzzled. A 2019 study by researchers at the Weizmann Institute of Science in Israel described five women who could smell normally despite having no olfactory bulbs, suggesting the brain can find alternative ways to smell in rare cases. “But the scientific community has been kind of silent on this because no one can explain how,” says Hummel.

9-17-21 By taking on poliovirus, Marguerite Vogt transformed the study of all viruses
When nobody else wanted the job, Marguerite Vogt stepped in. Working from early morning until late at night in a small, isolated basement laboratory at the California Institute of Technology, Vogt painstakingly handled test tubes and petri dishes under a fume hood: incubating, pipetting, centrifuging, incubating again. She was trying to grow a dangerous pathogen: poliovirus. It was 1952 and polio was one of the most feared diseases in America, paralyzing more than 15,000 people, mostly children, each year. Parents wouldn’t let their children play outside, and quarantines were instituted in neighborhoods with polio cases. Scientists were desperate for information about the virus, but many were hesitant to work with the infectious agent. “Everybody was afraid to go to that little lab in the basement,” says Martin Haas, professor of biology and oncology at the University of California, San Diego, and a personal friend and collaborator of Vogt’s for over three decades. Vogt, a brand-new research associate in the laboratory of Renato Dulbecco, took on the task of attempting to grow and isolate the virus on a layer of monkey kidney cells. The method was called a plaque assay for the distinctive round plaques that form when a single virus particle kills all the cells around it. Vogt didn’t tell her parents, both acclaimed scientists in Germany, that she was working with the virus. She later remarked that her father would have been very angry had he known of her poliovirus work, Haas says. After a year of persistence, Vogt succeeded (and remained virus-free). In 1954, she and Dulbecco published the method for purifying and counting poliovirus particles. It was immediately used by other scientists to study variants of poliovirus, and by microbiologist Albert Sabin to identify and isolate strains of weakened poliovirus to make the oral polio vaccine used in mass vaccination campaigns around the world.

9-17-21 Stone Age people used bone scrapers to make leather and pelts
At least 90,000 years ago, humans probably employed the tools to fashion clothes from animal skins. Discoveries in a Moroccan cave have provided a rare look at how Stone Age people may have turned animal skins into clothing. Bone tools, including hide scrapers and stone-tool sharpeners, were unearthed in Morocco’s Contrebandiers cave, say archaeologist Emily Hallett and colleagues. Dating of sediment, burned stones and animal teeth excavated there shows that the tools are around 90,000 to 120,000 years old, the scientists report September 16 in iScience. “Prior to major successful dispersals out of Africa and into Eurasia, Homo sapiens [were] making tools for various specialized functions, and those behaviors would have aided them [in] new environments,” says Hallett, of the Max Planck Institute for the Science of Human History in Jena, Germany. Different types of bone tools from around the time of the Moroccan finds have been unearthed at a handful of other African sites, though uses for many of those items remain unclear. Researchers have largely focused on an explosion of African bone tool styles that appeared around 44,000 years ago, after human expansions into Eurasia. Of 62 bone implements from the cave, seven were hide scrapers. These tools were crafted from pieces of antelope or wild cattle ribs that were split in half lengthwise and worked into a flat, spatula-like shape. Short, deep grooves and polish on these items resulted from scraping animal hides, the researchers say. The team unearthed the tools along with skinned animals’ bones. Patterns of stone-tool incisions on limb and jaw bones of sand foxes, golden jackals and wildcats resulted from detaching skin at the paws and pulling it over the head in one piece, providing evidence for the way the bone hide scrapers were used, the scientists say.

9-17-21 Fossil tracks may reveal an ancient elephant nursery
Preserved footprints of newborn pachyderms are roughly the size of drink coaster. Fossilized footprints found on a beach in southern Spain betray what may have been a nursery for an extinct species of elephant. The track-rich coastal site, which scientists have dubbed the Matalascañas Trampled Surface, is typically covered by 1½ meters of sand, says Clive Finlayson, an evolutionary biologist at the Gibraltar National Museum. But storm surges in the spring of 2020 washed away much of that sand and exposed the preserved footprints of ancient elephants, cattle, deer, pigs, wolves, water birds and even Neandertals, Finlayson and colleagues report September 16 in Scientific Reports. The sandy-clay sediments hosting this trove of tracks were probably laid down about 106,000 years ago, previous studies suggest. Among the newly uncovered tracks are the first-of-their-kind footprints of newborn straight-tusked elephants (Palaeoloxodon antiquus), an extinct species that probably died out during the last ice age (SN: 6/13/17). The teeny tracks — which measure 9.6 centimeters across, about the size of a drink coaster — suggest that the petite, possibly 2-month-old pachyderms stood about 66 centimeters tall at their shoulders and weighed around 70 kilograms, slightly heftier than a Newfoundland dog. Based on previous finds elsewhere of actual bones, adult straight-tusked elephants may have weighed 5.5 metric tons for females and a whopping 13 tons for males. The mix of elephant tracks at the site suggests that family groups including newborns, juveniles and adult females frequented the area and possibly used it as a nursery, the researchers say. Other fossils found at the site, including those preserving traces of ancient roots, hint that the area was rich in vegetation and speckled with lakes and ponds.

9-16-21 Prehistoric elephant nursery probably made easy prey for Neanderthals
More than 100,000 years ago, elephants raised their newborns among the dunes of the ancient Spanish coast. Fossil footprints suggest at least 14 calves, belonging to the extinct straight-tusked elephant (Palaeoloxodon antiquus), were part of a prehistoric nursery – and that they were hunted by Neanderthals. Carlos Neto de Carvalho at the Naturtejo UNESCO Global Geopark in Portugal and his colleagues identified the tracks on a broad fossil surface called the Matalascañas Trampled Surface (MTS) in Huelva, Spain, that contains the footsteps of antelope, birds, wolves and even Neanderthals. The researchers identified 34 sets of footprints attributed to the straight-tusked elephants, the local elephant species during the time the tracks were made – about 100,000 years ago, according to geological analysis of the rocks. Most of the footprints were left by infants that weighed between 70 and 200 kilograms. The tracks of adult elephants are rarer at the MTS site, but, based on track size, the researchers hypothesise that there are footprints of three adult females there. The footprint records match ecological observations of modern elephants, says de Carvalho, in which youngsters stay near to adult females with larger adult males rarely being present. “We describe elephant nursery and reproductive ecology in the fossil record for the first time,” he says. At the time the straight-tusked elephants roamed around what is now Huelva, the MTS was a pond that acted as a water source between coastal sand dunes. The water and nearby vegetation probably made a comfortable nursery for the young calves. But the secluded beach spot wasn’t free from predators. Footprints of Neanderthals have been discovered in the same track layers and researchers have even found stone tools made by the prehistoric people. While signs of interactions between people and pachyderms at the site have yet to appear, the team suggests that Neanderthals were drawn to the prospective hunting ground by the abundance of elephant calves. “A newly born elephant could be easy prey and just a delicious item in the Neanderthal menu,” says de Carvalho.

9-16-21 Having HPV while pregnant linked to increased risk of premature birth
Pregnant women infected with the human papillomavirus (HPV), which causes cervical cancer, are nearly four times more likely to give birth prematurely. The finding suggests that as more teenagers are vaccinated against HPV, there will be fewer premature births, says Helen Trottier at the University of Montreal in Canada. Premature babies are born smaller and are more prone to infections and numerous other health problems. HPV is a sexually transmitted virus that is shrugged off naturally by most people, but it can linger and cause cervical cancer, as well as anal and throat cancers and genital warts. Most high-income countries started offering HPV vaccination to teenagers about a decade ago. Rates of genital warts have started falling, although any effect on cervical cancer rates is taking longer to show up, as it takes many years to develop. Trottier wondered what the effects of the virus would be on pregnant women. Her team tested nearly 900 women for HPV in their vaginal fluid in the first and last three months of pregnancy. About 42 per cent tested positive at the start, and two-thirds of these still had the virus by the end. Those who had HPV throughout their pregnancy were 3.7 times more likely to either spontaneously go into early labour, or need to be induced to give birth early due to complications, compared with those who tested negative at the start. “We were surprised to see how strong was the association,” says Trottier. If the virus is directly causing the premature labour, the mechanism is unclear. HPV doesn’t cause inflammation, one known cause of premature births, but it could damage cells of the cervix, making them more vulnerable to bacterial infections that do cause inflammation, says Trottier.

9-16-21 Fossils and ancient DNA paint a vibrant picture of human origins
A century of science has begun to explain how and where Homo sapiens and our kin evolved. In The Descent of Man, published in 1871, Charles Darwin hypothesized that our ancestors came from Africa. He pointed out that among all animals, the African apes — gorillas and chimpanzees — were the most similar to humans. But he had little fossil evidence. The few known human fossils had been found in Europe, and those that trickled in over the next 50 years came from Europe and from Asia. Had Darwin picked the wrong continent? Finally, in 1924, a fortuitous find supported Darwin’s speculation. Among the debris at a limestone quarry in South Africa, miners recovered the fossilized skull of a toddler. Based on the child’s blend of humanlike and apelike features, an anatomist determined that the fossil was what was then popularly known as a “missing link.” It was the most apelike fossil yet found of a hominid — that is, a member of the family Hominidae, which includes modern humans and all our close, extinct relatives. That fossil wasn’t enough to confirm Africa as our homeland. Since that discovery, paleoanthropologists have amassed many thousands of fossils, and the evidence over and over again has pointed to Africa as our place of origin. Genetic studies reinforce that story. African apes are indeed our closest living relatives, with chimpanzees more closely related to us than to gorillas. In fact, many scientists now include great apes in the hominid family, using the narrower term “hominin” to refer to humans and our extinct cousins. In a field with a reputation for bitter feuds and rivalries, the notion of humankind’s African origins unifies human evolution researchers. “I think everybody agrees and understands that Africa was very pivotal in the evolution of our species,” says Charles Musiba, a paleoanthropologist at the University of Colorado Denver.

9-15-21 We should isolate when we have flu, not just covid-19
SEVERAL years ago, when I was working at a hospital in health research, I caught one of the bugs that were invariably transmitted around the building. I decided against commuting in, but I wasn’t so unwell that I couldn’t work from home. My manager informed me, however, that the hospital had a policy: if you are too ill to come to work, you are too ill to work from home. While the reasoning for this rule is sound, its effects may have been dangerous: to avoid taking a sick day and falling behind on work, many people would have gone to their office, risking transmission. Many companies now have policies against going into workplaces when ill, but it has taken a global pandemic to highlight what should be a basic ethical norm: an individual should be responsible for reducing the risk of passing on the pathogens they catch. One of the lessons of the covid-19 pandemic is that public health is everyone’s responsibility – or it should be. People feel a lot of pressure to work regardless of how they feel. A 2021 report from the Chartered Institute of Personnel and Development found, for example, that 75 per cent of surveyed UK employees reported presenteeism – continuing to work when sick or injured – in the workplace over the preceding 12 months. Presenteeism has a long history, but it seems that not even a global pandemic can stop it. Laws in the UK and the US explicitly prohibit intentionally or recklessly infecting another person with diseases, including covid-19 and sexually transmitted infections. And yet many people continue to work and expose themselves to others when sick, without legal consequences. Should these countries consider prosecuting a majority of working adults for breaking the law? Or decide that this behaviour isn’t obviously reckless? Neither, of course, is palatable.

9-15-21 The microbial gunk that hardens on teeth is revealing our deep past
Plaque fossilises while we are still alive. Now, dental calculus is giving up the secrets of our ancient ancestors, from what they ate to how they interacted and evolved. IT IS the only part of your body that fossilises while you’re still alive,” says Tina Warinner at the Max Planck Institute for the Science of Human History in Jena, Germany. To see what she is describing, stand in front of a mirror and examine the rear surfaces of your lower front teeth. Depending on your dental hygiene, you will probably see a thin, yellowish-brown line where the enamel meets the gum. This is plaque, a living layer of microbes that grows on the surface of teeth – or, more accurately, on the surface of older layers of plaque. If it isn’t brushed or scraped off, plaque hardens as minerals dissolved in saliva precipitate out into it, killing the microbes and petrifying them into a stony substance called dental calculus or tartar. To you and me, this rock-hard excrescence might seem rather repulsive, but it has become a chewy topic of research among archaeologists. Where it was once considered mere gobshite to be scraped off and discarded, it is now recognised as a time capsule extraordinaire. “Dental calculus is a treasure trove of information,” says Katerina Guschanski at Uppsala University in Sweden. Over the past 20 years, it has revealed some surprising and often quirky details of the lives of our ancestors. But recent research is far more ambitious. “We spent a number of years trying to understand dental calculus and how to use it to really get at some deeper evolutionary questions,” says Warinner. That is now paying off, and dental calculus is throwing light on big questions about where humans came from and where we are going. Warinner isn’t exaggerating when she says plaque “fossilises” – the process is exactly like permineralisation, when minerals in groundwater penetrate a dead organism and precipitate out, turning it into a fossil. Unlike underground fossilisation, however, dental calculus forms very rapidly: plaque can be fully calcified in just two weeks. The speed at which it fossilises means it captures vast amounts of biological detail over a lifetime. The principal component is entombed denizens of the oral microbiome, the huge and diverse assemblage of bacteria, archaea and fungi that live in and around your mouth. They account for about 90 per cent of calculus by volume, says Guschanski. But it also traps other things, including bits of food, pathogens, an individual’s own DNA and environmental debris such as dust and smoke particles. In fact, anything that finds its way into your mouth can end up being trapped in calculus. People’s drug histories have been probed via dental calculus. It has even been proposed as a way of telling whether someone has had covid-19.

9-15-21 Scientists in Egypt identify fossil of prehistoric 4-legged whale
A fossil discovered 13 years ago in Egypt's Western Desert has been identified as a prehistoric whale believed to have roamed 43 million years ago that had four legs and could live both on land and sea. Paleontologist Hesham Sallam, a professor at Mansoura University in Egypt, told The Associated Press earlier this week that environmentalists stumbled upon the fossil in an area that during prehistoric times was underwater. Researchers didn't start examining the fossil until 2017, and they published their findings for the first time last month in the journal Proceedings of the Royal Society B. The fossil whale has been named Phiomicetus Anubis, after the ancient Egyptian god of death, and had an elongated skull and snout. "We chose the name Anubis because it had a strong and deadly bite," Sallam told AP. "It could kill any creature it crossed paths with."

9-15-21 Saudi Arabia camel carvings dated to prehistoric era
A series of camel sculptures carved into rock faces in Saudi Arabia are likely to be the oldest large-scale animal reliefs in the world, a study says. When the carvings were first discovered in 2018, researchers estimated they were created about 2,000 years ago. This was based on their similarity to reliefs at Jordan's famous ancient city of Petra. But a fresh study puts the camels at between 7,000-8,000 old. Precisely ageing rock sculptures is a challenge for researchers. Unlike cave paintings, say, there is often no organic matter to sample. Rock art of this size is also rare in the region. The researchers, who published their findings in the Journal of Archaeological Science, assessed erosion patterns, analysed tool marks, and tested animal bones found at the site to determine a new date for the sculptures' creation. Their age makes them even older than such ancient landmarks as Stonehenge (5,000 years old) or the Pyramids at Giza (4,500 years old). They even predate the domestication of camels, a catalyst for economic development in the region. At the time of their creation, Saudi Arabia looked very different, with plains of grass dotted with lakes rather than the deserts of today. It is not clear why the camel sculptures were created, but the researchers have suggested that they could have provided a meeting point for nomadic tribes. They also noted the difficulty of making such works thousands of years ago. Many of the reliefs are high above the ground, meaning their carvers would have had to build scaffolding to create them.

9-15-21 Asteroid that wiped out dinosaurs shaped fortunes of snakes
Snakes owe their success in part to the asteroid strike that wiped out the dinosaurs, according to a new study. The impact caused devastation, with most animals and plants dying out. But scientists say a handful of surviving snake species were able to thrive in a post-apocalyptic world by hiding underground and going long periods without food. The resilient reptiles then spread out across the globe, evolving into the 3,000 or more species known today. The dinosaurs famously died out when an asteroid hit the Earth 66 million years ago, triggering earthquakes, tsunamis and wildfires, followed by a decade of darkness when ash clouds blocked out the Sun. An estimated 76% of plants and animals disappeared. But snakes, like some mammals, birds, frogs and fishes, managed to cling on to life. "In this environment of the collapse of food chains, snakes are able to survive and thrive, and they are able to colonise new continents and interact with their environment in new ways," said lead researcher Dr Catherine Klein, who carried out the research at the University of Bath. "It's likely that without this asteroid impact, they wouldn't be where they are today." At the time the asteroid slammed into Mexico, snakes were much like the ones we are familiar with today: legless with stretchy jaws for swallowing prey. With food in short supply, their ability to manage without food for up to a year and to hunt in the gloom following the catastrophe was likely instrumental in their survival. The handful of snake species that prevailed were mainly those that lived underground or on the forest floor, and in freshwater. With little competition from other animals, they had a blank canvas to branch out along different evolutionary paths and across the world, colonising Asia for the first time. Over the course of time, snakes become bigger and more widespread, exploiting new habitats, and new prey. New groups appeared, including giant sea snakes up to 10 metres long.

9-14-21 Piles of animal dung reveal the location of an ancient Arabian oasis
Fossilised piles of faeces, called middens, have revealed that a desert valley in Yemen was once a tropical oasis, which may have lasted in the dry region because of human land management practices. Today, Wadi Sana is a dry, rocky desert. We knew that between 11,000 and 5000 years ago, the Arabian peninsula and Sahara desert were wetter than they are now, and some lake-bed deposits suggested that grasslands and trees may have grown elsewhere in the interior of the peninsula. To find out more, Sarah Ivory at Pennsylvania State University and her colleagues turned to the petrified faeces of rock hyraxes (Procavia capensis). These small herbivorous mammals are native to parts of Africa and the Arabian peninsula and, despite their rabbit-like appearance, are kin to elephants and sea cows. Hyraxes live in colonies, defecating and urinating in a communal latrine. Many generations of them may inhabit the same location, and the layers of their concentrated waste material petrify in the dry air, creating a time capsule of local habitats because pollen and plant material are preserved in the faeces. Some hyrax middens date back 50,000 years. “Few other archives of information about past environments exist in dry places,” says Ivory. The researchers collected 24 middens in Wadi Sana, using a chemical dating process on 17 of them. The team also extracted fossilised pollen from 14 of these and classified it using a microscope. The pollen record shows that between 6000 and 4700 years ago, Wadi Sana was home to abundant tropical woodlands totally unlike anything there today. The region harboured frankincense and olive trees, as well as buttontrees (Terminalia), which today mostly grow along the foggy coastline. Elsewhere in the region, ecosystems were drying out and turning to desert as the monsoons weakened. But Wadi Sana was something of an oasis, partially thanks to the buttontrees that draw moisture from the air and pump it into the ground, but also because of the humans that moved there.

9-14-21 Sharon Peacock interview: How we track down new coronavirus variants
Last December, the UK shocked the world with the announcement of a new variant of the SARS-CoV-2 coronavirus that seemed to spread faster than the original virus. That discovery was made possible by the COVID-19 Genomics UK Consortium, which had been sequencing viral samples to monitor the evolution of the virus. COG-UK, as it is known, is led by Sharon Peacock, who spoke to New Scientist about her research. What were you working on before the pandemic kicked off? I was working in Thailand in disease research until 2009. When I came back to the UK, it was clear to me that genome sequencing of bacteria and viruses was on the cusp of being accessible to scientists in general. So I invested in understanding sequencing and how to apply it. My first study was looking at how sequencing performed in an MRSA [superbug] outbreak on a paediatric intensive care unit. At what point did you start thinking about sequencing the coronavirus? I was having conversations about the need for sequencing in early March 2020. People knew the virus would change because that’s what happens. By about 15 March, 20 of us got together and said, how would we set up a national sequencing capability? And the answer was to throw a net over everybody who could do it and say, come and help us. So the public health agencies, Wellcome Sanger Institute and 16 sequencing hubs around the country did. We didn’t waste any time. Did everyone agree that sequencing Some people thought the virus wouldn’t change enough to make it useful. The virus changes quite slowly, there’s limited genetic diversity compared to some other pathogens. But we continued anyway. And when October 2020 came and [significant] variants started to emerge, that meant that we were in a very strong position compared to some countries that had to really scale up quite quickly.

9-13-21 Rare genetic variants play important role in people who live to be 100
A close look at the DNA of centenarians – people aged over 100 years old – has identified rare genetic variants that might help explain their longevity. “Rare variants in ageing pathways affect human lifespan and constitute a part of the genetic architecture of human longevity,” says Zhengdong Zhang at Albert Einstein College of Medicine in New York. “There is an interplay between common and rare variants. Together they affect longevity, and I think that’s also true for any complex human trait.” Zhang and his team compared the genetic profiles of 515 centenarians and 496 non-centenarians – who were aged between 70 and 95. The researchers wondered whether the centenarians might owe their longevity in part to an absence of rare genetic variants known to increase the risk of disease. But they found that these “pathogenic rare variants” were as likely to be carried by centenarians as non-centenarians. On the flip side, some rare versions of genes known to have a beneficial effect on health were more likely to be carried by centenarians than non-centenarians. For instance, the researchers found the centenarians carried rare beneficial variants in something called Wnt signalling – which has a known role in the onset of cancer. This knowledge could be used to develop anti-ageing drugs that can target ageing mechanisms in general rather than treating individual age-related conditions to extend human lifespans, says Zhang. “This paper is intriguing due to the considerable [sample size] … These investigations are in essence challenging because large numbers are required to find statistically significant signals,” says Morten Scheibye-Knudsen at the University of Copenhagen in Denmark. “These exciting findings highlight the importance of human genetics in longevity research.”

9-13-21 A new company is trying to bring back the woolly mammoth. Expect 'tons of trouble' along the way.
A new company announced Monday that it's aiming to genetically resurrect the woolly mammoth, an oft-talked about endeavor that some scientists think could help fight climate change. The goal is to turn frozen tundra in Siberia back into grasslands, which can serve as effective carbon sinks. But Colossal's plan will undoubtedly raise many questions about the ethics of bringing back the ancient giants from the dead. "There's tons of trouble everyone is going to encounter along the way," Beth Shapiro, a paleogeneticist at the University of California, Santa Cruz, told The New York Times. Some of the main concerns have to do with the fact that mammoths have been extinct for thousands of years. Therefore, scientists may not know enough about their behavior, which means the animals — if Colossal or some other entity is ever indeed successful at bringing them back, which is far from a given — could suffer. For example, at the beginning at least, the mammoths wouldn't have mothers, Heather Bushman, a philosopher at the London School of Economics, pointed out. And if the species was "anything like elephants," they would have had "extraordinarily strong infant-mother bonds that last for a very long time," she told the Times. That leaves Bushman wondering who will look after the mammoths once they're on the ground. Read more at The New York Times.

9-9-21 Tooth decay has been a problem for primates for 54 million years
We are likely to develop dental cavities over time because sugars in our carbohydrate-rich diet support oral bacteria that release demineralising acids. Now there is evidence that the problem goes back to the early days of primate evolution. Microsyops latidens, a prehistoric primate that lived during the Early Eocene about 54 million years ago, also had to deal with cavities. “I was going through the [fossil] sample and I kept noticing these holes in their teeth and I wondered what they were,” says Keegan Selig at the University of Toronto Scarborough in Canada. “It was surprising even to see cavities in these critters, and then to see just how frequent they were was very surprising. We didn’t expect that they would be so common compared to living primates.” Selig and his colleague Mary Silcox, also at the University of Toronto Scarborough, examined the fossilised teeth of 1030 individuals collected from the southern Bighorn basin in Wyoming. They found that 7.48 per cent of individuals had cavities, a higher frequency than seen in most current living primates with the exception of some capuchins and tamarins. The M. latidens teeth are the oldest known evidence of dental cavities in any mammal, according to Selig and Silcox. M. latidens probably had a taste for high-sugar foods such as fruit, which could have led to these cavities if they were eating a lot of them. “These critters obviously didn’t have dental floss or toothbrushes, so you’d expect the cavities to kind of form everywhere, but the cavities only formed on the main chewing surface of the tooth, which is surprising. We don’t really know why,” says Selig. The fossils came from slightly different levels in the ancient rock sequence and so provide evidence of the M. latidens population over an extended period, perhaps over thousands of years. At certain levels in the sequence, the incidence of cavities was even higher; at one level, 17 per cent of individuals were affected. This fluctuation could be explained by changes in diet, say the researchers.

9-9-21 Infants may laugh like some apes in their first months of life
As babies age, their laughter starts to sound more like that of human adults. Babies may laugh like some apes a few months after birth before transitioning to chuckling more like human adults, a new study finds. Laughter links humans to great apes, our evolutionary kin (SN: 6/4/09). Human adults tend to laugh while exhaling (SN: 6/10/15), but chimpanzees and bonobos mainly laugh in two ways. One is like panting, with sound produced on both in and out breaths, and the other has outbursts occurring on exhales, like human adults. Less is known about how human babies laugh. So Mariska Kret, a cognitive psychologist at Leiden University in the Netherlands, and colleagues scoured the internet for videos with laughing 3- to 18-month-olds, and asked 15 speech sound specialists and thousands of novices to judge the babies’ laughs. After evaluating dozens of short audio clips, experts and nonexperts alike found that younger infants laughed during inhalation and exhalation, while older infants laughed more on the exhale. That finding suggests that infants’ laughter becomes less apelike with age, the researchers report in the September Biology Letters. Humans start to laugh around 3 months of age, but early on, “it hasn’t reached its full potential,” Kret says. Both babies’ maturing vocal tracts and their social interactions may influence the development of the sounds, the researchers say. A second trial in the new study with different audio clips and a new group of 100 novices also found that older infants seemed to laugh mainly on exhales. And participants of both trials reported that the more adultlike laughs were more pleasing to hear and contagious. That second finding suggests that the shift in laughter as infants age may partly happen due to unconscious affirmations from the babies’ parents, Kret says. Laughs during exhalation are clearer and louder than during inhalation, she says, sending a stronger signal during interactions that may be better for bonding.

9-9-21 Blood test could reveal who is most likely to get severe covid-19
A simple blood test could help predict which people with covid-19 are likely to get severely ill and need to go on a ventilator. The test measures levels of antibodies in the blood that are directed against molecules released by dead blood cells, including their own DNA. The test may also prove helpful in infected people before they reach the stage of needing hospital treatment, says Ana Rodriguez at NYU Langone in New York. It is likely to be less accurate in that group, but it could indicate who needs closer monitoring, she says. People who get severely ill from covid-19 tend to deteriorate at least a week or more after symptoms begin, when virus levels are falling, suggesting it is something about the person’s reaction to the infection that causes their problems, rather than the virus itself. Rodriguez’s team looked at blood tests done on 115 people admitted to hospital with covid-19 in 2020. About half of these people became severely ill and needed oxygen support, while the rest recovered quickly. Those with high levels of antibodies directed against DNA or a fatty molecule from cell membranes called phosphatidylserine had about a 90 per cent chance of deteriorating. But the test only identified about a quarter of people who got worse. “It won’t mean we catch everybody but if you have this, it looks very bad,” says Rodriguez. It is unclear if the antibodies detected by the test are involved in the person’s deterioration, or if they are innocent bystanders. The DNA and phosphatidylserine seem to come from red blood cells that have burst open, as well as immune cells called neutrophils that release their DNA as they die in a bid to trap bacteria. It is possible that the antibodies may bind to the DNA, contributing to the formation of multiple tiny blood clots, which is often seen in severe covid-19 and causes strokes and kidney damage. Doctors currently make covid-19 treatment decisions based on people’s clinical signs, such as their blood oxygen levels, and their age and other risk factors.

9-8-21 What we know so far about booster shots and the covid-19 vaccines
AS A growing body of data suggests that vaccine-induced protection from covid-19 declines over time, many nations are gearing up to roll out a booster programme. Israel has already begun, while the US, France and Germany have all announced plans to begin rolling out third doses. Some other countries, including the UK, are holding back, with results from a key trial of third shots expected imminently. The Joint Committee on Vaccination and Immunisation, which advises UK health departments, has been mulling over booster shots for some time. In June, it issued interim advice that any potential booster scheme should be offered in two stages from September, starting with care home residents, front-line healthcare and social care workers, people aged over 70 and adults who are clinically extremely vulnerable or immunosuppressed. But this is largely yet to materialise: all that has been announced so far is a limited programme of third shots for people who have severely weakened immune systems. There has been speculation since early in the development of the coronavirus vaccines that booster doses would be needed, perhaps to combat newer variants. But time is also a factor. For many diseases, the strength of the immune response – stemming from either natural infections or vaccines – wanes over time periods ranging from months to years. Several studies have shown that, as expected, antibody levels fall gradually in the months after coronavirus vaccination. Antibodies aren’t the whole story, as the memory cells that make antibodies and other immune cells called T-cells can persist in various sites in the body, ready to spring into action if needed, but it is much harder to detect these in people via tests. However, we can measure how well vaccines are working in practice at stopping people from getting ill. Studies of covid-19 vaccination have given varying estimates of this. Recent Israeli data caused concern when it showed a person’s protection from infection could be as low as 40 per cent roughly six months after the nation’s vaccination programme began, although protection against severe disease seemed to be holding up, at 91 per cent.

9-8-21 mRNA cancer therapy now in human trials after shrinking mouse tumours
A cancer treatment that uses messenger RNA to launch an immune attack on cancer cells can completely shrink tumours in mice and is now being tested in people. Messenger RNAs – or mRNAs – are molecules that instruct cells to make proteins. They have risen to fame with the roll out of mRNA covid-19 vaccines. BioNTech, the German company that developed Pfizer’s mRNA covid-19 vaccine, is now testing whether mRNAs can be used to treat cancer by stimulating cells to produce tumour-fighting proteins. The company made a mixture of four mRNAs that instruct cells to produce four proteins called cytokines that are naturally released by immune cells to attack cancer cells. When they injected these mRNAs directly into melanomas in 20 mice, immune cells within the tumours began producing large amounts of the desired cytokines. This produced an immune response that caused the skin tumours to completely disappear in all but one of the mice in less than 40 days. In another experiment, mice that had melanomas as well as lung tumours were treated with the mRNA mixture. The mRNAs were only injected into the melanomas, but they also suppressed the growth of the lung tumours. This may be because the immune cells activated by the mRNAs were able migrate to the distant tumours, says Timothy Wagenaar at Sanofi, a pharmaceutical company that is partnering with BioNTech to develop the treatment. The mice didn’t display any side effects and didn’t lose weight during the treatment. Following these promising results, BioNTech and Sanofi are now testing the safety of the mRNA mixture in 231 people with advanced melanoma, breast cancer and other solid tumours. They presented preliminary results of the first 17 patients at the Society for Immunotherapy of Cancer annual meeting in November 2020, showing they had no serious side effects. Future trials will test how well the therapy works.

9-8-21 5 fruit and veg, 8 hours’ sleep: Should we trust daily health targets?
Many of us aim for “recommended dailies” such as 10,000 steps, 2000 calories or 2 minutes of tooth brushing. But where do these figures come from and are they supported by evidence? FOR as long as I can remember, certain numbers have inhabited my head: Five fruit and veg a day, 8 hours of sleep, 2000 calories, 2 minutes of tooth brushing, eight glasses of water, 10,000 steps. For want of a better term, these are the “recommended dailies”: numbers that are etched onto our brains as the ones we should live by. But for all their influence, it is unclear whether sticking dutifully to them actually makes a difference to our health. So I decided to get to the bottom of things, attempting to live my own life by the numbers (see “Living the dream”, page 41) while also digging into some critical questions about them: who came up with these figures in the first place? How solid is the scientific basis for these magic numbers? More to the point, is sticking to them really worth the effort? Keeping your teeth clean isn’t just a way to avoid the dentist’s drill (and bill) – the bacteria that cause gum disease have also been linked to an increased risk of developing Alzheimer’s. People with gum disease also have a two to three times greater risk of having a stroke or heart attack, and while a causal link hasn’t been shown, there are suggestions that gum disease increases markers of inflammation in the blood. The benefit of brushing is that as it removes thin films of plaque bacteria from the teeth, it breaks up bacterial communities, disrupting the opportunity for social evolution. This essentially stops them evolving into super bacteria that are experts at causing decay. Where the “rule” about brushing for 2 minutes, twice a day comes from isn’t clear (Public Health England is unsure of its origins, despite the recommendation appearing on National Health Service sites), and there is conflicting evidence on how much, and how often, is actually needed.

9-8-21 Recommended daily health targets can save us from ourselves
LIVING to a ripe old age owes a fair amount to luck, but if science can tell us anything about health, it is that our judgement matters, too. The way we live our lives and the way we treat our bodies can make a huge difference to our chances of having a long and healthy life. This is the basic message encoded in the generic health targets that we all carry in our heads: five pieces of fruit or veg a day, 8 hours of sleep, 10,000 steps, 2000 calories and so on. Yet on closer inspection, many of the best-known nuggets of health advice owe more to marketing and folklore than they do to science. The 10,000 steps per day that so many people aim to take seem to have been largely plucked from nowhere. Even dentists can’t tell you why they recommend brushing specifically for 2 minutes, twice a day, as our feature on page 38 reveals. To make matters worse, even advice that stems from decades of research comes from epidemiological studies, which follow large numbers of people over many years. Translating this kind of data into one-size-fits-all advice is notoriously difficult for the simple reason that we aren’t all the same. The number of hours you need to sleep for can vary by 7 hours depending on your age, for example. Then there is the ideal number of steps, which differs depending on whether you are hiking up the side of a mountain or ambling around a shopping mall. And since science’s work is never done, even solid health advice can, and does, change. With this much complexity, it is tempting to just ditch living by numbers. Yet targets do have a part to play in health education. Even though fewer than a third of UK adults actually manage to consume five portions of fruit and vegetables a day, the average child at primary school can recite the guideline, so at least has internalised the message that eating plants is good for you.

9-7-21 A pinch of saturated fat could make tempering chocolate a breeze
Phospholipids are key to achieving a melt-in-the-mouth texture. Glossy, velvety chocolate that snaps in the fingers and melts in the mouth is the chocolatier’s dream. But crafting cocoa confections with this optimal texture is no easy feat. The endeavor, known as tempering, demands carefully warming and cooling liquid chocolate until it crystallizes into its most delectable form. Now, scientists may have found a shortcut: adding a small pinch of fatty molecules called phospholipids, researchers report August 31 in Nature Communications. With phospholipids, “you can simplify the whole tempering process, making sure you always have the right quality of the chocolate,” says food chemist Alejandro Marangoni of the University of Guelph in Canada. Curious about what occurs on a molecular level during tempering, Marangoni and colleagues focused on the ingredient that gives chocolate its texture — cocoa butter. While previous tempering research had targeted cocoa butter’s main component, triglycerides, the team set its sights on a different sweet spot: the minor components, which include free fatty acids and phospholipids. Removing these minor components from the cocoa butter and adding them back in one by one allowed the researchers to figure out each component’s role during tempering. With just a pinch of phospholipids added to the cocoa butter — achieving a weight concentration of 0.1 percent of the chocolate’s total — the mixture rapidly crystallized into the elusive, melt-in-the-mouth texture. The process required a single cooling to 20° Celsius rather than multiple heating and cooling cycles as tempering typically demands. Next, the team increased the phospholipid weight concentration in melted dark chocolate by an extra 0.1 percent, and easily produced high-quality textures again. The result suggests that phospholipids could be used to simplify chocolate tempering.

9-6-21 Men fart more when eating a plant-based diet due to good gut bacteria
Plant-based diets cause men to fart more and have larger stools, researchers have found – but that seems to be a good thing, because it means these foods are promoting healthy gut bacteria. Anecdotally, it is well-known that eating more plants – including fruit, vegetables, grains and legumes – creates bulkier stools and increases flatulence. However, few studies have measured these changes or related them to changes in gut bacteria. Claudia Barber at the Liver and Digestive Diseases Networking Biomedical Research Centre in Barcelona, Spain, and her colleagues compared the effects of a Mediterranean-style diet mostly comprised of plants with a Western-style diet containing fewer fruit and vegetables on the guts of 18 healthy men aged between 18 and 38. Each participant was randomly assigned to follow one of the diets for two weeks, then after a break, they switched to the other diet for two weeks. The men did a similar number of poos per day on the two diets, but each one was about double the size while they were on the plant diet. The men collected and weighed their own stools using digital scales and found they produced about 200 grams per day on the plant diet, compared with 100 grams on the Western diet. This is because eating plants promotes certain types of bacteria in our guts that make food for themselves by fermenting plant fibre, says Rosemary Stanton at the University of New South Wales in Sydney, Australia. The added stool weight is made up of the spent bodies of these extra bacteria plus water and a small amount of undigested plant fibre, she says. Some of the specific fibre-fermenting bacteria that became more abundant in the men’s guts while they were on the plant diet included Agathobaculumand anaerostipes and Agathobaculum butyriciproducens, an analysis of their waste showed.

9-3-21 Mix-and-match antibiotic prescriptions may help lower resistance risk
Antibiotic resistance is one of the biggest threats to public health, yet a surprisingly simple tactic could help to tackle it: alternating between three different antibiotic medicines daily. The approach has so far only been tested on bacteria grown in a dish, but using this approach with commonly used antibiotics killed bacteria five times more efficiently than using one drug at a time. If trials in people give similar results, it could be used to combat antibiotic resistance by asking people to take a different drug out of three every day, says Hinrich Schulenburg at the University of Kiel in Germany. Antibiotics are seen as one of the greatest developments of modern medicine, transforming potential killers like wound infections and tuberculosis into something treatable with a course of tablets. But the potency of this group of medicines is waning, because bacteria can mutate to become resistant to their effects and new drugs are not being developed fast enough. There are global campaigns to try to husband our remaining antibiotics by reducing their use. Doctors already change to a different antibiotic if the bacteria causing an infection become resistant to the first drug used, typically after a few weeks. Schulenburg’s group wondered if a strategy of rapid switching from the outset would be helpful. The team showed in 2018 that if bacteria in a dish are treated with rapid switching between three antibiotics that work through different mechanisms, the microbes take longer to develop resistance than if the medicines are cycled over slower time-scales of a few weeks. The experiment used levels of antibiotics lower than normally given to people, to encourage resistance to develop. In the latest study they found the rapid-cycling approach was even more potent if they used three closely related antibiotics, from a class called beta-lactams. These are often used to treat Pseudomonas aeruginosa bacteria, which can cause wound infections and pneumonia.

9-3-21 How personalized brain organoids could help us demystify disorders
Clumps of brain cells made from people with Rett syndrome had abnormal electrical activity. Clumps of brain cells grown from the stem cells of two people with a neurological syndrome show signs of the disorder. The results, published August 23 in Nature Neuroscience, suggest that personalized brain organoids could be powerful tools to understand complex disorders. Researchers are eager to create brain organoids, human stem cells coaxed into becoming 3-D blobs of brain cells, because of their ability to mimic human brains in the lab (SN: 2/20/18). In the current study, researchers grew two kinds of brain organoids. One kind, grown from healthy people’s stem cells, produced complex electrical activity that echoed the brain waves a full-sized brain makes. These waves, created by the coordinated firing of many nerve cells, are part of how the brain keeps information moving (SN: 3/13/18). The researchers also grew organoids using cells from a 25-year-old woman and a 5-year-old girl with Rett syndrome, a developmental disorder marked by seizures, autism and developmental lags. Rett syndrome is thought to be caused by changes in a gene called MECP2, mutations that the lab-grown organoids carried as well. These organoids looked like those grown from healthy people, but behaved differently in some ways. Their nerve cells fired off signals that were too synchronized and less varied. Some of the brain waves these organoids produced are reminiscent of a brain having a seizure, in which a bolus of electrical activity scrambles normal brain business. With organoids carrying Rett syndrome mutations, scientists can better understand the syndrome and even begin to test possible treatments. Organoids might yield insights into other disorders, too, says coauthor Bennett Novitch, a developmental neuroscientist at the David Geffen School of Medicine at UCLA. “Work on this front is already under way in labs around the world.”

9-2-21 Rapidly evolving bits of DNA helped develop the human brain
Many of the fastest-evolving sections of the human genome are involved in brain development. These rapidly changing segments of DNA may have played key roles in the evolution of the human brain and in our cognitive abilities. Chris Walsh at Boston Children’s Hospital in Massachusetts and his colleagues studied sections of the human genome dubbed “human accelerated regions” (HARs). These stretches of DNA are virtually identical in many other mammals that have been studied, suggesting they have important functions – but they differ in humans, implying our evolution has changed them. Previous studies have identified 3171 possible HARs, but Walsh says it is unlikely that they are all important. “Probably hundreds of them are, but probably not thousands,” he says. His team set out to identify HARs that have played important roles in the evolution of our brains. The researchers placed copies of each HAR, as well as their chimpanzee equivalents, into developing brain cells from mice and humans. In each cell line, they tracked how much each gene in the genome was expressed. This allowed them to determine whether each HAR enhanced the activity of genes, compared with the equivalent sequence from a chimp. Using this and other methods, the team identified 210 HARs that significantly enhanced gene activity in the human neural cells. These HARs probably affect human brain development. The researchers then zeroed in on a gene called PPP1R17, which is expressed in some of the cells of the developing brain and regulated by several HARs, so it therefore behaves differently in humans than in other mammals. They compared the expression of PPP1R17 in the developing brains of mice, ferrets, rhesus macaques and humans. In the macaques and humans, the gene was expressed in the cerebral cortex, but it wasn’t in the mice and ferrets.

9-2-21 Stone Age humans or their relatives occasionally trekked through a green Arabia
Long-ago rains drew hominids in phases to what’s now dry desert. Arabia, known today for its desert landscape, served as a “green turnstile” for migrating Stone Age members of the human genus starting around 400,000 years ago, a new study finds. Monsoon rains periodically turned northern Arabia into a well-watered oasis, creating windows of opportunity for long-ago humans or their relatives to trek through that crossroads region from starting points in northern Africa and southwest Asia. That’s the implication of a series of five ancient lake beds of varying ages, each accompanied by distinctive stone tools, unearthed at a northern Saudi Arabian site called Khall Amayshan 4, or KAM 4. Sediments from the lake beds, which were linked to periods when the climate was wetter than today, also yielded fossils of hippos, wild cattle and other animals. Like hominids, those creatures must have migrated into the region along rain-fed lakes, wetlands and rivers, an international team reports online September 1 in Nature. Until now, the oldest stone tools in Arabia dated to at least 300,000 years ago (SN: 11/29/18). Previous finds only hinted that Stone Age Homo sapiens or other Homo species temporarily inhabited green, wetter parts of Arabia, a conclusion largely resting on discoveries at two other Saudi sites, each preserving stone tools from a single point in time (SN: 11/1/18). Aside from providing the earliest known evidence of hominids in Arabia, the new finds demonstrate for the first time that ancient Homo groups traveled there when conditions turned wet, say archaeologist Huw Groucutt of the Max Planck Institute for the Science of Human History in Jena, Germany, and colleagues. As a result, northern Arabia could have served as a key, if intermittent, passageway out of Africa for humans or close evolutionary relatives who reached South Asia by around 385,000 years ago (SN: 1/31/18), southern China between 120,000 and 80,000 years ago (SN: 10/14/15) and the Indonesian island of Sumatra between 73,000 and 63,000 years ago (SN: 8/9/17).

9-1-21 What would Earth be like if life had never existed?
Earth would be a very different place to our familiar home if life had never existed. The composition and chemistry of the atmosphere would be completely different, so this would profoundly affect the climate and the physical processes forming the land. If we were to visit such a place, we would surely find it a completely hostile and alien world on which we couldn’t survive. Although life began about 3.5 billion years ago, it largely remained single-celled and anaerobic for almost 2 billion years. When photosynthetic bacteria developed, they slowly changed the planet’s atmosphere from one comprised of mostly carbon dioxide and nitrogen with trace amounts of oxygen to a more oxygen-rich one. This oxygen assisted the development of the more complex eukaryotic cell and so the eventual rise of multicellular life. It also precipitated out iron oxides, forming all those red soils around the world. Without that oxygen, there would also be no ozone layer filtering out damaging UV radiation. With no life, the initial high levels of carbon dioxide would have remained in the atmosphere since no removal as marine carbonates could have occurred. So goodbye white cliffs of Dover in the UK and the limestone formations that make up our landscapes. Without life, Earth might be similar to Venus. There would be no oxygen, but abundant carbon dioxide, which could create a runaway greenhouse effect, evaporating the oceans. There would also probably be sulphur and nitrogen oxides in the atmosphere, resulting in sulphuric and nitric acid rain. Plate tectonics might stall without oceans, so there would be no mountain chains, just large volcanoes punching through a global crust of granite, erupting infrequently but catastrophically. The vast range of terrestrial rocks we know today, including slate, limestone, chalk and all other sedimentary rocks, would be absent.

9-1-21 Cartilage from the nose used to treat two people's knee osteoarthritis
Implants made from nose cartilage have been used to repair the knee joints of two people with severe osteoarthritis. A larger clinical trial is now planned to see if the treatment can help the millions of people with knee osteoarthritis worldwide. Knee osteoarthritis occurs when cartilage in the knee joint gradually wears away, leading to pain, stiffness and difficulty walking. It is common in the elderly, but some young people can develop it too. The only way to treat the condition is to replace the knee with an artificial joint made of metal or plastic. But these prosthetic joints can wear out too, leading to more surgery. Ivan Martin at the University of Basel in Switzerland and his colleagues wondered if another option may be to replace damaged knee cartilage with healthy cartilage taken from the nose. “The main target advantage is the effective regeneration of the cartilage, as opposed to substitution by a foreign body part,” he says. After successful experiments in mice and sheep, the researchers tried this in a 34-year-old man and a 36-year-old woman with severe knee osteoarthritis. First, they removed small amounts of cartilage from each person’s nasal septum – the structure separating the nostrils – and grew it in dishes to make thin, flat sheets. Surgeons then inserted these cartilage grafts into the man and the woman’s damaged knee joints. MRI scans showed that the nose cartilage successfully integrated into their joints. Eight months after the procedure, both reported significantly less pain, better knee function and quality of life. Both were able to avoid having traditional knee replacements. “A larger clinical test is a now a must to test efficacy, as the two cases treated can only provide anecdotal evidence,” says Martin.

9-1-21 The surprising upsides of spite and how to harness them
In an era of social media cancelling, our nasty side has never been more prominent. But the latest research suggests that, when wielded right, petty ill will can be a force for good. A MAN buys a house next door to his ex-wife and installs a 4-metre bronze statue of a hand, middle finger raised, facing her window. A prominent investor buys a company so he can fire the management he dislikes, even though he stands to lose money. People take their time at the checkout to annoy the next customer, buy gnomes for their garden to antagonise a neighbour and slow down to annoy tailgaters, even though it puts everyone in danger. Examples of spiteful behaviour, harming another at some cost to yourself, aren’t hard to find. As a psychological game where no one wins, spite is puzzling: we may wonder why it wasn’t weeded out by evolution long ago. Instead, in a competitive era of identity politics, all too often played out on social media, it seems more prevalent than ever. Yet, compared with other social behaviours like selfishness, cooperation and altruism, there has been relatively little psychological research into why we do it. With potentially far-reaching consequences for both political stability and individual mental health, it has never been more important to understand this dark side of human behaviour. For many years, most of the research into spite came from the field of behavioural economics: the study of how human decision-making differs from what you would expect from a purely rational point of view. Classical economists dreamed up the concept of Homo economicus, a person who only ever acts to maximise their own rewards. If offered a choice between something and nothing, Homo economicus would always take what is on offer. In experiments, however, this isn’t how everyone behaves. In the Ultimatum Game, created by economist Werner Güth at the University of Cologne in Germany in 1977, one volunteer is given a pot of money and asked to decide how much of it to share with another player. If the other player accepts the offer, both will keep their share of the cash. But if the other player refuses the offer, both leave empty-handed. They only play the game once.

9-1-21 The hard problem of consciousness is already beginning to dissolve
Science can solve the great mystery of consciousness – how physical matter gives rise to conscious experience – we just have to use the right approach, says neuroscientist Anil Seth. THE nature of consciousness is truly one of the great mysteries of the universe because, for each of us, consciousness is all there is. Without it, there is no world, no self, no interior and no exterior. There is nothing at all. The subjective nature of consciousness makes it difficult even to define. The closest we have to a consensus is that there is “something it is like to be conscious”. There is something it is like to be me or you, and probably something it is like to be a dolphin or a mouse. But there is – presumably – nothing it is like to be a bacterium or a toy robot. The challenge is to understand how and why this can be true. How do conscious experiences relate to the cells and molecules and atoms inside brains and bodies? Why should physical matter give rise to an inner life at all? Some people fear science may not be up to the task. They point out that you can’t precisely control or observe felt experiences. Some even question the idea that physical mechanisms can ever explain consciousness. I disagree. I believe that science is capable of explaining consciousness, but only if we stop treating it as a single big mystery requiring a humdinger solution. Instead, we must break it down into its various related properties and address each in turn. As we progressively explain why particular patterns of brain activity map to particular kinds of conscious experience, we will find that the deeper mystery of consciousness itself begins to fade away. Humans have pondered the relationship between physical matter and conscious experience for a long time. In the 1600s, René Descartes divided the universe into “mind stuff” (res cogitans) and “matter stuff” (res extensa), raising the conundrum of how the two might ever interact. His dualist perspective is now accompanied by a bewildering array of alternatives, ranging from illusionism – the proposal that consciousness doesn’t exist, at least not in the sense that we normally think of consciousness – to panpsychism, which posits that consciousness is fundamental and ubiquitous. The relatively orthodox scientific view of physicalism – the view that I find most appealing – is that consciousness is related to or emerges from physical matter. The question is how.

9-1-21 Perspective-changing experiences, good or bad, can lead to richer lives
Even people facing tough times can achieve a good life. In December, my husband, our 5-year-old daughter and I tested positive for COVID-19. Life, already off-kilter, lurched. Smell, taste, breath — were they normal? The air smelled only of cold; everything tasted vaguely of cardboard. The state mailed us a pulse oximeter to read oxygen levels from our fingers. The device beeped when those levels dipped too low — a seemingly objective measure during a subjective time. We used the device with abandon, only my husband regularly triggering the alarm. He went to bed, where he stayed for days, or maybe it was weeks. Time distilled into moments: remote school, meals, Christmas, pulse-ox, beep. We exited quarantine on January 1, the day of fresh starts. Except my once energetic 8-year-old son, who somehow never tested positive, now loafed in front of the heater for hours. My husband, his breathing still abnormal and his fatigue lingering, raged. Ever the extrovert, I absorbed their emotions as my own. My risk calculation shifted, as despair overshadowed the fear of disease. The sickness we had hid from for so long had found us anyway. Were we now immune? Should we proceed just as before? Prior to the sickness, I’d been researching pandemic fatigue, a term used to describe the boredom that can arise during a protracted crisis like the one we’re in now (SN Online: 2/15/21). “People prefer action to inaction,” social psychologist Erin Westgate of the University of Florida in Gainesville told me. For some, that compulsion toward the experiential runs deep, she and colleagues reported in 2014 in Science. When the researchers gave college students a choice between sitting idly in a quiet room or pushing a button to receive an electric shock, a startling number went for the shock. I have been seeking, and pushing, that button all my life. I’ve taught English in Japan, worked as a national park ranger and, following an unfortunate series of events, sold pineapples along a tourist highway in Hawaii in exchange for a tent over my head. Westgate’s recent work suggests that button pushing sorts often flourish in rich and aesthetic environs. I took heed. Against the dreary backdrop of being homebound in a global health crisis, I signed up for private pottery lessons, drawn viscerally to the idea of creating something from mud.

40 Evolution News Articles
for September 2021

Evolution News Articles for August 2021