Woolly mammoths and Neanderthals may have shared genetic traits

Mammoth rendering.

A new Tel Aviv University study suggests that the genetic profiles of two extinct mammals with African ancestry -- woolly mammoths, elephant-like animals that evolved in the arctic peninsula of Eurasia around 600,000 years ago, and Neanderthals, highly skilled early humans who evolved in Europe around 400,000 years ago -- shared molecular characteristics of adaptation to cold environments.

The research attributes the human-elephant relationship during the Pleistocene epoch to their mutual ecology and shared living environments, in addition to other possible interactions between the two species. The study was led by Prof. Ran Barkai and Meidad Kislev of TAU's Department of Archaeology and Ancient Near Eastern Cultures and published on April 8 in Human Biology.

"Neanderthals and mammoths lived together in Europe during the Ice Age. The evidence suggests that Neanderthals hunted and ate mammoths for tens of thousands of years and were actually physically dependent on calories extracted from mammoths for their successful adaptation," says Prof. Barkai. "Neanderthals depended on mammoths for their very existence.

"They say you are what you eat. This was especially true of Neanderthals; they ate mammoths but were apparently also genetically similar to mammoths."

To assess the degree of resemblance between mammoth and Neanderthal genetic components, the archaeologists reviewed three case studies of relevant gene variants and alleles -- alternative forms of a gene that arise by mutation and are found at the same place on a chromosome -- associated with cold-climate adaptation found in the genomes of both woolly mammoths and Neanderthals.

The first case study outlined the mutual appearance of the LEPR gene, related to thermogenesis and the regulation of adipose tissue and fat storage throughout the body. The second case study engaged genes related to keratin protein activity in both species. The third case study focused on skin and hair pigmentation variants in the genes MC1R and SLC7A11.

"Our observations present the likelihood of resemblance between numerous molecular variants that resulted in similar cold-adapted epigenetic traits of two species, both of which evolved in Eurasia from an African ancestor," Kislev explains. "These remarkable findings offer supporting evidence for the contention regarding the nature of convergent evolution through molecular resemblance, in which similarities in genetic variants between adapted species are present.

"We believe these types of connections can be valuable for future evolutionary research. They're especially interesting when they involve other large-brained mammals, with long life spans, complex social behavior and their interactions in shared habitats with early humans."

According to the study, both species likely hailed from ancestors that came to Europe from Africa and adapted to living conditions in Ice Age Europe. The species also both became extinct more or less at the same time.

"It is now possible to try to answer a question no one has asked before: Are there genetic similarities between evolutionary adaptation paths in Neanderthals and mammoths?" Prof. Barkai says. "The answer seems to be yes. This idea alone opens endless avenues for new research in evolution, archaeology and other disciplines.

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New state of matter: Elements can be solid and liquid at same time

Potassium.

Scientists have discovered a new state of physical matter in which atoms can exist as both solid and liquid simultaneously.

Until now, the atoms in physical material were understood to exist typically in one of three states -- solid, liquid or gas. Researchers have found, however, that some elements can, when subjected to extreme conditions, take on the properties of both solid and liquid states.

Applying high pressures and temperatures to potassium -- a simple metal -- creates a state in which most of the element's atoms form a solid lattice structure, the findings show. However, the structure also contains a second set of potassium atoms that are in a fluid arrangement.

Under the right conditions, over half a dozen elements -- including sodium and bismuth -- are thought to be capable of existing in the newly discovered state, researchers say.

Until now, it was unclear if the unusual structures represented a distinct state of matter, or existed as transition stages between two distinct states.

A team led by scientists from the University of Edinburgh used powerful computer simulations to study the existence of the state -- known as the chain-melted state. Simulating how up to 20,000 potassium atoms behave under extreme conditions revealed that the structures formed represent the new, stable state of matter.

Applying pressure to the atoms leads to the formation of two interlinked solid lattice structures, the team says. Chemical interactions between atoms in one lattice are strong, meaning they stay in a solid form when the structure is heated, while the other atoms melt into a liquid state.

The study, published in the journal Proceedings of the National Academy of Sciences, was supported by the European Research Council and the Engineering and Physical Sciences Research Council. The work was carried out in collaboration with scientists from Xi'an Jiantong University in China.

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Are brown dwarfs failed stars or super-planets?

Artist rendering of a brown dwarf. They are more massive and hotter than planets but lack the nuclear fusion in their core as in normal stars. Two such “failed” stars were detected orbiting the star ? Ophiuchi. They were probably formed in the earlier protoplanetary disk of the star.

Brown dwarfs fill the "gap" between stars and the much smaller planets -- two very different types of astronomical objects. But how they originate has yet to be fully explained. Astronomers from Heidelberg University may now be able to answer that question. They discovered that the star ν Ophiuchi in the Milky Way is being orbited by two brown dwarfs, which in all probability formed along with the star from a gas and dust disk, just as planets do. The research results were published in Astronomy & Astrophysics.

Brown dwarfs orbit either one star or travel in isolation in the vast expanse of the Milky Way. Their mass -- they are at least 13 times heavier than the planet Jupiter -- is sufficient to generate, at least temporarily, energy in their core through nuclear fusion. They are not sufficiently massive, however, to ignite hydrogen in their cores and hence to create their own light. The heat they continue to radiate after formation is how astronomers are able to locate them. It is estimated that up to 100 billion brown dwarfs make their home in the Milky Way. Yet it remains unclear how they form -- whether they are "failed" stars or possibly even super-planets.

The recent discoveries made at the Centre for Astronomy of Heidelberg University (ZAH) could provide an answer. Prof. Dr Andreas Quirrenbach and his team at the Königstuhl State Observatory of the ZAH analysed the variations in radial velocity of the star ν Ophiuchi. Using telescopes in the USA and Japan, the Heidelberg astronomers and others measured the velocity of the star for 11 years. The star has a mass slightly greater than two and half times that of the Sun, and is located approximately 150 light years from Earth in the constellation Ophiuchus.

The Heidelberg team noticed a certain pattern in the measurements, similar to those caused by orbiting planets or binary stars, which is usually nothing out of the ordinary. But in this case, in-depth analysis of the data revealed something extraordinary: apparently, ν Ophiuchi is being orbited by two brown dwarfs with an orbital period of approximately 530 and 3,185 days, which puts them in a 6:1 resonant configuration. So, the brown dwarf closest to ν Ophiuchi orbits its star exactly six times while the other, more distant brown dwarf completes only one orbit.

This discovery sheds completely new light on the evolution of brown dwarfs. Do they develop exclusively like normal stars in interstellar clouds, or can they also form in the so-called protoplanetary disk of gas and dust that surrounds the parent star in the early phase of its formation? "The 6:1 resonance is a strong indication for the latter scenario," explains Prof. Quirrenbach. "Only then could the orbits of the newly developing brown dwarfs adjust to a stable resonance over millions of years."

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Life could be evolving right now on nearest exoplanets

The intense radiation environments around nearby M stars could favor habitable worlds resembling younger versions of Earth.

Rocky, Earth-like planets orbiting our closest stars could host life, according to a new study that raises the excitement about exoplanets.

When rocky, Earth-like planets were discovered orbiting in the habitable zone of some of our closest stars, excitement skyrocketed -- until hopes for life were dashed by the high levels of radiation bombarding those worlds.

Proxima-b, only 4.24 light years away, receives 250 times more X-ray radiation than Earth and could experience deadly levels of ultraviolet radiation on its surface. How could life survive such a bombardment? Cornell University astronomers say that life already has survived this kind of fierce radiation, and they have proof: you.

Lisa Kaltenegger and Jack O'Malley-James make their case in a new paper, published in Monthly Notices of the Royal Astronomical Society. Kaltenegger is associate professor of astronomy and director of Cornell's Carl Sagan Institute, at which O'Malley-James is a research associate.

All of life on Earth today evolved from creatures that thrived during an even greater UV radiation assault than Proxima-b, and other nearby exoplanets, currently endure. The Earth of 4 billion years ago was a chaotic, irradiated, hot mess. Yet in spite of this, life somehow gained a toehold and then expanded.

The same thing could be happening at this very moment on some of the nearest exoplanets, according to Kaltenegger and O'Malley-James. The researchers modeled the surface UV environments of the four exoplanets closest to Earth that are potentially habitable: Proxima-b, TRAPPIST-1e, Ross-128b and LHS-1140b.

These planets orbit small red dwarf stars which, unlike our sun, flare frequently, bathing their planets in high-energy UV radiation. While it is unknown exactly what conditions prevail upon the surface of the planets orbiting these flaring stars, it is known that such flares are biologically damaging and can cause erosion in planetary atmospheres. High levels of radiation cause biological molecules like nucleic acids to mutate or even shut down.

O'Malley-James and Kaltenegger modeled various atmospheric compositions, from ones similar to present-day Earth to "eroded" and "anoxic" atmospheres -- those with very thin atmospheres that don't block UV radiation well and those without the protection of ozone, respectively. The models show that as atmospheres thin and ozone levels decrease, more high-energy UV radiation reaches the ground. The researchers compared the models to Earth's history, from nearly 4 billion years ago to today.

Although the modeled planets receive higher UV radiation than that emitted by our own sun today, this is significantly lower than what Earth received 3.9 billion years ago.

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Revolutionary camera allows scientists to predict evolution of ancient stars

For the first time scientists have been able to prove a decades old theory on stars thanks to a revolutionary high-speed camera.

Scientists at the University of Sheffield have been working with HiPERCAM, a high-speed, multicolour camera, which is capable of taking more than 1,000 images per second, allowing experts to measure both the mass and the radius of a cool subdwarf star for the first time.

The findings published today (8 April 2019) in Nature Astronomy have allowed researchers to verify the commonly used stellar structure model -- which describes the internal structure of a star in detail -- and make detailed predictions about the brightness, the colour and its future evolution.

Scientists know that old stars have fewer metals than young stars, but the effects of this on the structure of stars was, until now, untested. Old stars (often referred to as cool subdwarf stars) are faint and there are few in the solar neighbourhood.

Up until now scientists have not had a camera powerful enough to be able to get precise measurements of their stellar parameters such as the mass and the radius.

HiPERCAM can take one picture every millisecond as opposed to a normal camera on a large telescope which usually captures only one picture every few minutes. This has given scientists the ability to measure the star accurately for the first time.

Professor Vik Dhillon, Dr Steven Parsons and Dr Stuart Littlefair, from the Department of Physics and Astronomy at the University of Sheffield, led the HiPERCAM project in partnership with the Science and Technology Facilities Council's Astronomy Technology Centre (ATC) and the Instituto de Astrofisica de Canarias, along with researchers from the University of Warwick and Durham University.

Professor Dhillon said: "Now we have been able to measure the size of the star we can see it is in line with stellar structure theory. These results would not have been possible with any other telescope.

"This not only proves stellar structure theory, but has also verified the potential of HiPERCAM."

The paper is the first to be published using HiPERCAM data, which is mounted on the Gran Telescopio Canarias (GTC) -- the world's largest optical telescope, with a 10.4 metre mirror diameter.

The camera can take high-speed images of objects in the universe, allowing their rapid brightness variations -- due to phenomena such as eclipses and explosions -- to be studied in unprecedented detail.

Data captured by the camera, taken in five different colours simultaneously, allow scientists to study the remnants of dead stars such as white dwarfs, neutron stars and black holes.

The GTC is based on the island of La Palma, situated 2,500 metres above sea level, which is one of the best places in the world to study the night sky.

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Are you with me? New model explains origins of empathy

Researchers at the Max Planck Institute and the Santa Fe Institute have developed a new model to explain the evolutionary origins of empathy and other related phenomena, such as emotional contagion and contagious yawning. The model suggests that the origin of a broad range of empathetic responses lies in cognitive simulation. It shifts the theoretical focus from a top-down approach that begins with cooperation to one that begins with a single cognitive mechanism.

According to Fabrizio Mafessoni, who is a post-doctoral researcher at the Max Planck Institute for Evolutionary Anthropology, standard theoretical models of the origins of empathy tend to focus on scenarios in which coordination or cooperation are favored.

Mafessoni, and his co-author Michael Lachmann, a theoretical biologist and Professor at the Santa Fe Institute, explored the possibility that the cognitive processes underlying a broad range of empathetic responses -- including emotional contagion, contagious yawning, and pathologies like echopraxia (compulsive repetition of others' movements) and echolalia (compulsive repetition of others' speech) -- could evolve in the absence of kin selection or any other mechanism directly favoring cooperation or coordination.

Mafessoni and Lachmann posited that animals, including humans, can engage in the act of simulating the minds of others. We cannot read other minds -- they are like black boxes to us. But, as Lachmann explains, all agents share almost identical "black boxes" with members of their species, and "they are constantly running simulations of what other minds might be doing." This ongoing as-actor simulation is not necessarily geared toward cooperation: it's just something humans and animals do spontaneously.

An example of this process is represented by mirror neurons: it has been known for some time that the same neurons engaged in planning a hand movement are also used when observing the hand movement of others. Mafessoni and Lachmann wondered what the consequences would be if they were to extend that process of understanding to any social interaction.

When they modeled outcomes rooted in cognitive simulation, they found that actors engaged in as-actor simulation produce a variety of systems typically explained in terms of cooperation or kin-selection. They also found that an observer can occasionally coordinate with an actor even when this outcome is not advantageous. Their model suggests that empathetic systems do not evolve solely because agents are disposed to cooperation and kin-selection. They also evolve because animals simulate others to envision their actions. According to Mafessoni, "the very origin of empathy may lie in the need to understand other individuals."

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Hello, kitty: Cats recognize their own names, according to new Japanese research

Cats can learn to recognize their own names.

Pet cats can recognize their own names if their names are used regularly by their owners, according to new results by a team of researchers in Japan.

The research was performed largely within the lab of Professor Toshikazu Hasegawa from the University of Tokyo with Atsuko Saito, Ph.D., first author of the research paper. Saito is now an associate professor at Sophia University in Tokyo.

Evolution of social cats

This is the first project to study cats' ability to understand human voices. Other research projects have discovered that apes, dolphins, parrots, and dogs can understand some words spoken by humans.

Saito speculates that mammals like dolphins and apes are naturally social animals and are therefore more inclined to interact with humans and respond to human cues.

"In comparison to those other species, cats are not so social. Cats interact with us when they want," said Saito.

Projects to understand simple social behaviors like name recognition in cats may give clues to how we humans became social. Both humans and cats have evolved through the process of self-domestication, where the population rewards certain traits that then become increasingly common in future generations.

"There may be a common feature in the evolutionary process of sociality between humans and cats. Since cats are still evolving to become more domesticated, there is a possibility that we can see the process of evolution of sociality by investigating the social cognition in cats," said Saito.

What's in a name?

To test if a cat recognized its name, researchers tested the name against other similar-sounding nouns. For example, a cat named Kari would also hear recordings of the words hifu (skin) and shuto (capital city).

Researchers played recordings of their own voices and the cat's owner's voice saying five words: the first four words were the similar-sounding nouns and the final, fifth word was the cat's name.

Researchers decided that cats responded to their name if they ignored recordings of other words, but moved their ears or heads when they heard their name. Cats rarely responded more enthusiastically, for example by moving their tails or bodies or by using their voice.

Cats who showed habituated weak responses to other similar-sounding nouns or the names of other cohabiting cats were significantly more likely to show strong responses to their own names.

Researchers state that a cat that did not respond to its name may still be able to recognize its name.

"Their lack of response may be caused by their low motivation level to interact with humans, or their feelings at the time of the experiment," said Saito.

Saito offers simple advice to any cat owners wishing to increase their communication with their cat: "Please interact with your cat when she shows that she wants to interact with you."

Single or many cats?

Researchers also tested if cats can distinguish between their own names and those of other cohabitating cats. Cats living in homes were more likely than cats living in a cat café to distinguish between their own names and the names of cohabitating cats.

Cat cafés are businesses where people pay for a drink and to interact with the many cats who live in the café.

Researchers suspect that owners use their cats' names specifically at home, whereas cat café visitors may use the cats' names interchangeably.

Researchers analyzed data from 77 different cats in the research project, which was broken into four separate experiments performed over three years.

Cats studied in the research were between six months to 17 years old, a mix of male and female, and were mostly mixed breeds. Most cats were spayed/neutered and all but one were indoor-only cats.

Professor Toshikazu Hasegawa is now retired from the University of Tokyo.

Research scientist Kazutaka Shinozuka, Ph.D., from the RIKEN Center for Brain Science also contributed to this research.

According to previous research, cats can distinguish between their owner's voice and a stranger's voice, can follow a person's pointing finger to find hidden food, and may change their behavior depending on their owner's facial expressions.

Read more at Science Daily

Melting glaciers causing sea levels to rise at ever greater rates

Regional share of glaciers in sea-level rise from 1961 to 2016.

Melting ice sheets in Greenland and the Antarctic as well as ice melt from glaciers all over the world are causing sea levels to rise. Glaciers alone lost more than 9,000 billion tons of ice since 1961, raising water levels by 27 millimeters, an international research team under the lead of the University of Zurich has now found.

Glaciers have lost more than 9,000 billion tons (that is 9,625,000,000,000 tons) of ice between 1961 and 2016, which has resulted in global sea levels increasing by 27 millimeters in this period. The largest contributors were glaciers in Alaska, followed by the melting ice fields in Patagonia and glaciers in the Arctic regions. Glaciers in the European Alps, the Caucasus and New Zealand were also subject to significant ice loss; however, due to their relatively small glacierized areas they played only a minor role when it comes to the rising global sea levels.

Combination of field observations and satellite measurements

For the new study, the international research team combined glaciological field observations with geodetic satellite measurements. The latter digitally measure the surface of the Earth, providing data on ice thickness changes at different points in time. The researchers were thus able to reconstruct changes in the ice thickness of more than 19,000 glaciers worldwide. This was also possible thanks to the comprehensive database compiled by the World Glacier Monitoring Service from its worldwide network of observers, to which the researchers added their own satellite analyses. "By combining these two measurement methods and having the new comprehensive dataset, we can estimate how much ice has been lost each year in all mountain regions since the 1960s," explains Michael Zemp, who led the study. "The glaciological measurements made in the field provide the annual fluctuations, while the satellite data allows us to determine overall ice loss over several years or decades."

335 billion tons of ice lost each year

The global mass loss of glacier ice has increased significantly in the last 30 years and currently amounts to 335 billion tons of lost ice each year. This corresponds to an increase in sea levels of almost 1 millimeter per year. "Globally, we lose about three times the ice volume stored in the entirety of the European Alps -- every single year!" says glaciologist Zemp. The melted ice of glaciers therefore accounts for 25 to 30 percent of the current increase in global sea levels. This ice loss of all glaciers roughly corresponds to the mass loss of Greenland's Ice Sheet, and clearly exceeds that of the Antarctic.

From Science Daily

Medical guidelines may be biased, overly aggressive in US

Dr. Sunita Sah practiced general medicine for several years in the United Kingdom's National Health Service. When she came to the United States, she noticed something strange.

The U.K. guidelines for tests such as mammograms and colon cancer screenings drastically differed from those in the U.S. -- even though they were based on the same medical evidence.

"Having colonoscopy at the age of 50 -- that struck me as rather odd when I moved to the U.S., because you don't really hear about people having colonoscopies as a screening procedure in the U.K.," said Sah. "It's much less invasive to test for blood in the stool. It's also less costly and doesn't have the risks of undertaking a colonoscopy."

Now an assistant professor of management and organizations at Cornell, Sah and Ismail Jatoi of the University of Texas Health, San Antonio, say the treatment guidelines recommended by medical specialist organizations are more likely to call for greater use of health care services and exacerbate overdiagnosis, overtreatment and spiraling health care costs. Their commentary, "Clinical Practice Guidelines and the Overuse of Health Care Services: Need for Reform," appeared March 18 in the Canadian Medical Association Journal.

The implications are significant, she said, because guidelines are supposed to provide standard evidence-based treatment practices for all doctors.

"The recommendations put out by specialty organizations -- like the American College of Cardiology or the American College of Radiology -- show specialty bias in recommending more aggressive and/or more frequent screening procedures," said Sah, an expert on conflict of interest. "In the U.S. in particular, where the fee-for-service compensation model dominates medicine, which is different from countries like the U.K., you see even more recommendations for greater use of health care services."

Specialty bias refers to the tendency of physicians to recommend the treatments in which they are trained to deliver. For example, localized prostate cancer can be treated with either surgery or radiation.

"If you go to a surgeon, chances are that they are more likely to recommend that you have surgery; if you go to a radiation oncologist, they are more likely to recommend that you have radiation," she said. "They each often believe that the treatment that they're trained in is the better one."

In the case of screening for colorectal cancer, the American College of Gastroenterology's panel -- all of whom were gastroenterologists -- recommended colonoscopy as the best strategy.

But the United States Preventive Task Force, with no gastroenterologists or gastrointestinal surgeons, recommended testing the stool, sigmoidoscopy (an exam of only the lower part of the colon) or colonoscopy as a last resort. Stool testing was also recommended by the European Society of Medical Oncology panel, which consisted of six medical oncologists, no gastroenterologists and one gastrointestinal surgeon. The panel said there was limited evidence that screening colonoscopy is effective.

"Colonoscopies are more invasive than stool testing and come with potentially greater risks and costs for patients -- but increased clinical volume and profits for gastroenterologists," Sah said.

Specialty guidelines are also subject to fee-for-service bias, according to the commentary. Doctors who receive a payment for each treatment may tend to recommend that treatment more often, because they have a financial interest in it.

"The bias is not necessarily malicious or intentional," Sah said. "In a fee-for-service environment, they may be biased to do more rather than less, so it becomes a habit."

But more is not necessarily better, she said. "Sometimes the risks of those procedures are just not worth the benefits."

The authors call for a reduction in conflicts of interest in the fee-for-service model, and more professional diversity in the makeup of the guideline committees. "You need a variety of different voices on those committees," Sah said.

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Digging ancient signals out of modern human genomes

With new genome analysis tools, scientists have made significant advances in our understanding of modern humans' origins and ancient migrations.

But trying to find ancient DNA, let alone prove that the ancient DNA is ancestral to a population living today is extremely challenging.

A new study in Molecular Biology and Evolution (MBE) adds to this understanding by reconstructing artificial genomes with the analyses of the genome of 565 contemporary South Asian individuals to extract ancient signals that recapitulate the long history of human migration and admixture in the region.

"All in all, our results provide a proof-of-principle for the feasibility of retrieving ancient genetic signals from contemporary human subjects, as if they were genomes from the past embedded in amber," said Luca Pagani, the research coordinator of the study.

The study was led by Burak Yelmen and Mayukh Mondal from the Institute of Genomics of the University of Tartu, Estonia and coordinated by Luca Pagani from the same institution and from the University of Padova, Italy.

"The genetic components we managed to extract from modern genomes are invaluable, given the shortage of ancient DNA available from South Asian human remains, and allow us to elucidate the genetic composition of the ancient populations that inhabited the area," said Burak Yelmen, co-first author of the study.

While studying the mixing events that brought ancient human populations to form contemporary South Asians, the researchers also noted that some portion of the genomes had not mixed as expected, as if the genetic variants that evolved in South Asia or the ones that arrived from West Eurasia were important for adapting to the local lifestyle through admixture.

"Among these variants, we found genes important for immunity and for dietary changes, as one may expect for human populations adapting to new sets of pathogens or food," said Mayukh Mondal, joint first author of this work.

The human evolution of skin pigmentation also revealed many genetic variants for the population studied.

"Intriguingly we also noted that some genetic variants implicated in the skin pigmentation of West Eurasians were under opposite selective forces, some becoming highly frequent and others being almost lost after the admixture events. Skin pigmentation is surely a fascinating and complex subject and we are still trying to understand what, if any, would be the adaptive implications of the signal we detected."

The study will add to the growing picture of the diversity of South Asians, and future studies of modern human population origins.

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