Giant viruses may simply be a 'Frankenstein' of smaller viruses

Bubbling nitrifying activated sludge tank at a wastewater treatment plant in Klosterneuburg, Austria. This was the source of the sludge samples used for microcolony sorting.

Viruses have a ubiquitous presence in the world. Their population is estimated to be 1031, 10 times greater than the nonillion (1030) of microbes on the planet -- a figure that surpasses the number of stars in the Milky Way. Giant viruses are characterized by disproportionately large genomes and virions that house the viruses' genetic material. They can encode several genes potentially involved in protein biosynthesis, a unique feature which has led to diverging hypotheses about the origins of these viruses. But after discovering a novel group of giant viruses with a more complete set of translation machinery genes than any other virus known to date, scientists at the U.S. Department of Energy Joint Genome Institute (DOE JGI), a DOE Office of Science User Facility, believe that this group (dubbed "Klosneuviruses") significantly increases our understanding of viral evolution.

The predicted hosts for the Klosneuviruses are protists (single-celled eukaryotic (nucleus-containing) microorganisms) and while their direct impacts on protists are not yet worked out, these giant viruses are thought to have a large impact on these protists that help regulate the planet's biogeochemical cycles. DOE JGI published the findings in the journal Science on April 7, 2017 with collaborators from the National Institutes of Health, University of Vienna, and CalTech.

"The discovery presents virus evolution for us in new ways, vastly expanding our understanding of how many essential host genes viruses can capture during their evolution," said National Institutes of Health evolutionary and computational biologist Eugene Koonin, a study co-author whose lab collaborated with DOE JGI on analyzing the Klosneuvirus genome. "Since protein synthesis is one of the most prominent hallmarks of cellular life, it shows that these new viruses are more 'cell-like' than any virus anyone has ever seen before."

Scientists have been fascinated by giant viruses since 2003, when a group of French biologists led by Didier Raoult discovered the Mimiviruses. Since then, a handful of other giant virus groups have been found. The unique ability among them to encode proteins involved in translation (typically DNA to RNA to protein) piqued researchers' interests as to the origin of giant viruses. Since then, two evolutionary hypotheses have emerged. One posits that giant viruses evolved from an ancient cell, perhaps one from an extinct fourth domain of cellular life. Another -- a scenario championed by Koonin -- presents the idea that giant viruses arose from smaller viruses.

The discovery of Klosneuvirus supports the latter idea, according to Tanja Woyke, DOE JGI Microbial Genomics Program lead and senior author of the paper. "In this scenario, a smaller virus infected different eukaryote hosts and picked up genes encoding translational machinery components from independent sources over long periods of time through piecemeal acquisition," she said.

At first glance, the suite of "cellular" genes in Klosneuvirus seemed to have a common origin, but when analyzing them in detail, the research team observed they came from different hosts. From the evolutionary trees the team built, they noticed that they were acquired by the viruses bit by bit, at different stages in their evolution. The Klosneuvirus genes contained aminoacyl-tRNA (transfer ribonucleic acid) enzymes with specificity for 19 out of 20 amino acids, along with more than 20 tRNAs and an array of translation factors and tRNA modifying enzymes -- an unprecedented finding among all viruses, including the previously known giant viruses.

JGI postdoctoral researcher Frederik Schulz and Woyke unearthed Klosneuvirus while analyzing microcolony sequence data from a wastewater treatment plant sample in Klosterneuburg, Austria. This data was generated under a DOE JGI Community Science Program (CSP) project focused on the diversity of nitrifying bacteria for converting ammonia to nitrate in industrial and sewage waste treatment. "We expected genome sequences of nitrifying bacteria in the microcolony sequence data," Woyke said. "Finding a giant virus genome took the project into a completely new and unexpected, yet very exciting direction."

When Schulz, the study's first author, noticed that several of the metagenomes were viral in origin, he and Woyke conducted analyses to determine their source. They found that the Klosneuvirus group came from a novel viral lineage affiliated with Mimiviruses.

"Mining sequence data in DOE JGI's Integrated Microbial Genomes & Microbiomes system, which houses thousands of metagenomes, allowed us to find evolutionary relatives of our Klosneuvirus," Schulz said. He notes that while the metagenomic discovery of Klosneuviruses helped answer important evolutionary questions, the actual biological function of the translation system genes remains elusive -- at least until these viruses are grown in the laboratory together with their hosts.

Read more at Science Daily

Hubble takes close-up portrait of Jupiter

This dazzling Hubble Space Telescope photo of Jupiter was taken when it was comparatively close to Earth, at a distance of 415 million miles. Hubble reveals the intricate, detailed beauty of Jupiter's clouds as arranged into bands of different latitudes, known as tropical regions. These bands are produced by air flowing in different directions at various latitudes. Lighter colored areas, called zones, are high-pressure where the atmosphere rises. Darker low-pressure regions where air falls are called belts. The planet's trademark, the Great Red Spot, is a long-lived storm roughly the diameter of Earth. Much smaller storms appear as white or brown-colored ovals. Such storms can last as little as a few hours or stretch on for centuries.

On April 3, 2017, as Jupiter made its nearest approach to Earth in a year, NASA's Hubble Space Telescope viewed the solar system's largest planet in all of its up-close glory. At a distance of 415 million miles (668 million kilometers) from Earth, Jupiter offered spectacular views of its colorful, roiling atmosphere, the legendary Great Red Spot, and it smaller companion at farther southern latitudes dubbed "Red Spot Jr."

The giant planet is now at "opposition," positioned directly opposite the sun from the Earth. This means that the sun, Earth and Jupiter line up, with Earth sitting between the sun and the gas giant. Opposition also marks Jupiter's closest point to us, and the planet appears brighter in the night sky than at any other time in the year.

This positioning allowed a team led by Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland to observe Jupiter using Hubble's Wide Field Camera 3. Hubble photographed exquisite details in Jupiter's atmosphere, as small as about 80 miles (129 kilometers) across.

With its immense and powerful storms and hundreds of smaller vortices, the atmosphere of Jupiter is divided into several distinct, colorful bands, parallel to the equator. These bands, with alternating wind motions, are created by differences in the thickness and height of the ammonia ice clouds; the lighter bands rise higher and have thicker clouds than the darker bands. The bands are separated by winds that can reach speeds of up to 400 miles (644 kilometers) per hour.

Jupiter is best known for the Great Red Spot, an anticyclone that has raged for at least 150 years. This famous storm is larger than Earth. However, the Great Red Spot is slowly shrinking -- a trend seen since the late 1800s. The reason for this phenomenon is still unknown. Hubble will continue to observe Jupiter in hopes of solving this mysterious riddle.

The images are part of the Outer Planets Atmospheres Legacy program or OPAL. This program provides yearly Hubble global views of the outer planets to look for changes in their storms, winds, and clouds. It began in 2014 with Uranus, and has been studying Jupiter and Neptune since 2015. In 2018, it will begin viewing Saturn.

The team timed the Hubble observation to coincide with when NASA's space probe Juno would be near its closest point to Jupiter, so that scientists could get concurrent observations.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

From Science Daily

Married couples with common ancestry also share similar genes

When two married people appear similar, it isn't necessarily a coincidence.

When two married people appear similar, it isn't necessarily a coincidence, but may be related to the tendency to marry someone with the same ancestry; a trend that can have important effects on the genetics of different populations, report Ronnie Sebro of the University of Pennsylvania, and senior authors Josée Dupuis from the Boston University School of Public Health and Neil Risch from the University of California, San Francisco, in a study published April 6th, 2017 in PLOS Genetics.

Until recently, most people picked a spouse from within their local community, and that person often had the same ancestry. Over many generations, this affinity for similar mates has created a genetic structure in the population which has the potential to bias the results of genetic studies. In the first investigation into mating patterns across multiple generations within a U.S. population, researchers explored genetic similarity between spouses from three generations of white people in the Framingham Heart Study, an ongoing examination of heart health in the residents of Framingham, Massachusetts, which began in 1948.

Using genomic data, they characterized the ancestry of 879 participant spouse pairs and observed that individuals of Northern European, Southern European and Ashkenazi ancestry preferentially chose spouses of the same background. In each successive generation, however, individuals were less likely to choose a spouse with the same ancestry. They also showed that the mating patterns caused spouses to be more genetically similar to each other than might otherwise be expected, and that the genetic structure created by these mating patterns in the population has decreased over time.

The findings from this study reflect demographic patterns and how they have changed during the past 60 years in Framingham, Massachusetts. Genetic similarity within a population can be important to consider in genomic studies because it can lead to false positives when identifying gene regions that are associated with a disease, and affect estimates of the degree to which a disease is passed on through one's genes.

From Science Daily

Archaeologists Discover Remains of 3,700-Year-Old Egyptian Pyramid

The remains of an Egyptian pyramid built around 3,700 years ago have been discovered near the well-known "bent pyramid" of King Snefru, the antiquities ministry announced on Monday.

The pyramid from the 13th dynasty was found in Dahshur's royal necropolis, some 30 kilometers (20 miles) south of Cairo, it said.

"An alabaster... block engraved with 10 vertical hieroglyphic lines" was among the finds, the ministry said, citing Adel Okasha, director general at the necropolis.

It said granite lintel and stone blocks were discovered that would show more "about the internal structure of the pyramid.”

Excavation is still in its early stages and the size of the pyramid has not yet been established.

Blocks of stone and the beginning of a corridor which was discovered can be seen in photos provided by the ministry.

The corridor "leads to the interior of the pyramid, extended by a ramp and the entrance to a room,"the ministry said.

"All the discovered parts of the pyramid are in very good condition and further excavation is to take place to reveal more parts," it said.

Egypt, home of one of the world's earliest civilizations, boasts 123 ancient pyramids, Zahi Hawass, former head of the Supreme Council of Antiquities, told AFP.

Hawass, who took part in the last discovery of a new pyramid in Egypt in 2008 at Saqqara, just south of Cairo, said the remnants in Dahshur appeared to indicate that the monument belonged to "a queen buried near her husband or her son."

"The hope now is to find any inscription which can reveal the identity of the owner of this pyramid," the archaeologist said. “To find the name of a previously unknown queen would be an addition to history.”

Egypt's ancient treasures include the world-famous Pyramids of Giza, constructed around 4,500 years ago.

The Khufu pyramid, or Great Pyramid, is the largest of the three in Giza, standing at 146 meters (480 feet) tall, and the only surviving structure of the seven wonders of the ancient world.

Khufu and Khafre in Giza along with the Bent and Red pyramids in Dahshur are part of Operation ScanPyramids, with teams scanning the structures in search of hidden rooms and cavities.

The project to unearth still hidden secrets of the pyramids applies a mix of infrared thermography, radiographic imaging and 3D simulation — all of which the researchers say are non-invasive and non-destructive.

In October last year, the team announced that two additional cavities had been found in the Great Pyramid after another scan a year earlier found several thermal anomalies.

Read more at Discovery News

Early Human Cannibals Didn’t Eat Each Other for the Calories

When early humans, including our species, ate their own kind, it was more likely for ritual purposes than for a nourishing meal, according to an unusual study released Thursday.

Carving up the human body to calculate the caloric value of each part, the study argues that prehistoric cannibalism — while less rare than widely assumed — was a dangerous undertaking offering relatively meagre nutritional rewards.

Kilo for kilo, a wild horse, bear, or boar had more than three times the calories in fat and protein than our lean-and-mean human ancestors, who were mostly skin, muscle, and bone, according to the research, published in the journal Scientific Reports.

Moreover, human prey — as wily as the hunter — would surely put up a good fight before being sliced up into filets.

"I did the study because I wanted to know how nutritional we are compared to these other animals," explained James Cole, a senior lecturer in archaeology at the University of Brighton in England.

"That might tell us whether we, and other human species, were doing it for the calories, or if there is some other explanation," he told AFP.

The findings help flesh out the idea that cannibalism among homo sapiens — as well as Neanderthals, homo erectus and other hominins — was suffused with cultural meaning.

Recent scholarship suggests our ancestors, including Neanderthals, had rich cultures, evidenced by artifacts, jewelry and perhaps language.

"It seems unreasonable to think that early humans wouldn't have had as complex an attitude to cannibalism as we modern humans," Cole said. "They may have had as many reasons to consume each other as we do."

"It's not just about the meat," he added.

Sucking the marrow from a leg bone or gnawing on a spleen might have been a way to affirm territorial control and pay homage to deceased family members, Cole said.

"The consumption of the food in that scenario is a kind of bonus," he pointed out.

More broadly, the study suggests that our cave- or savannah-dwelling cousins were probably far more sophisticated than we suspect.

'Brain matter'
 
A review of the fossil record, along with recent genetic research, shows that cannibalism among hominin species, or early man, was fairly common.

"We don't have a lot of human remains," Cole said. "But even within that small sample, we still see quite a lot of evidence of human modification on those remains — butchery, cut marks on the bone — consistent with cannibalism."

Bones with cut marks at the tendon joints to remove filets of muscle; long arm and leg bones that have been cracked to access the marrow; human teeth marks — all are telltale signs of humans feasting on humans.

The earliest confirmed case of human cannibalism — found in a cave in Spain — features the species homo antecessor and dates back nearly one million years.    

Other research has shown that prehistoric humans developed some immunity to diseases, known as transmissible spongiform encephalopathies (TSE), that are spread by eating infected brain matter.

"The only reason an evolutionary adaptation would develop is if you are over-exposed to the pathogens," Cole said.

That could have arisen when a human ate, say, a lion that had consumed a bovine brain.

The human variant of mad cow disease that erupted in the 1990s spread when people ate beef from cows that had been fed the brains of infected animals.

"Or it comes from eating the brain matter of members of our own species," as is thought to have occurred with the Fore people of Papua New Guinea, who practiced cannibalism.

A wide range of motivations are used to explain modern-day cannibalism, ranging from psychosis (think of the liver-and-fava-bean loving Hannibal Lecter), to warfare, medicine or funerary ritual. Shipwreck and plane crashes can also lead to survival cannibalism.

Read more at Discovery News

Neptune's journey during early planet formation was 'smooth and calm'

Artist's conception of a loosely tethered binary planetoid pair like those studied by Fraser et al. in this work which led to the conclusion that Neptune's shepherding of them to the Kuiper Belt as gradual and gentle in nature.

Dr Wes Fraser from Queen's led an international research project 'Colours of the Outer Solar Systems Origins Survey' Col-OSSOS, which uses data collected from the Frederick C. Gillett Gemini North Telescope and Canada-France-Hawaii Telescope (CFHT) both on Maunakea in Hawaii. By simultaneously using two world class telescopes, Dr Fraser's team was able to produce unique research with a global impact.

The study focused on the Kuiper Belt -- a region of space beyond the gas giant Neptune. The area holds more than 1,700 known icy objects, which are remnants of the early Solar System. Normally objects that are formed in this area are red in colour.

However, during his research Dr Fraser identified a small number of 'oddball' objects, which stand out as uniquely blue and are zipping around in binary pairs that orbit around each other, like the moon orbits Earth.

Astronomers have always thought that these objects formed in the heart of the Kuiper Belt but Dr Fraser's findings, which have been published in Nature Astronomy, suggest that the blue binaries actually formed in a region much closer to the Sun and were then shepherded by Neptune's gravitational nudges onto their current orbits in the distant Kuiper Belt several billions of years ago.

Dr Fraser's research indicates that when Neptune moved from 20 AU to its current location at 30 AU, this was a very slow and calm movement, which allowed the fragile and loosely bound binaries to be pushed out a similar distance to where they are found currently without being disrupted into two separate single objects.

Discussing the significance of the findings, Dr Fraser said: "This research has opened the window to new aspects of understanding the early stages of planet growth. We now have a solid handle on how and where these blue binaries originated.

"There has been some evidence around how Neptune moved outwards to 30 AU. Our hypothesis about how these blue binaries came to be where they are requires that Neptune's migration was largely a smooth and calm movement.

"This novel programme uses two world-class telescopes: the Gemini-North and Canada-France-Hawaii telescopes, simultaneously. In doing so, we are able to gather comprehensive spectral information spanning the ultra-violet, optical, and near-infrared wavelength ranges. Without this programme and the partners involved, this major research breakthrough would not have been possible."

Meg Schwamb, astronomer at the Gemini Observatory, commented: "Working closely together, Gemini North and the Canada-France-Hawaii telescopes coordinated their movements to observe the Col-OSSOS Kuiper belt objects at nearly the same time."

"These simultaneous observations on Maunakea allowed us to measure the light from the same side of the Kuiper Belt object, removing one of the main challenges in studying Solar System bodies that rotate."

Todd Burdullis, QSO operations specialist at CFHT who helped to co-ordinate the observations, commented: "Facilitating the simultaneous observations with the Col-OSSOS team and Gemini Observatory was challenging, but paved the way for a greater understanding of the origins of these blue binaries.

Read more at Science Daily

10,000 years of genetic continuity in northwest North America, study reveals

Researchers are analyzing DNA from ancient individuals found in southeast Alaska, coastal British Columbia, Washington state and Montana. A new genetic analysis of some of these human remains finds that many of today's indigenous peoples living in the same regions are descendants of ancient individuals dating to at least 10,300 years ago.

A study of the DNA in ancient skeletal remains adds to the evidence that indigenous groups living today in southern Alaska and the western coast of British Columbia are descendants of the first humans to make their home in northwest North America more than 10,000 years ago.

"Our analysis suggests that this is the same population living in this part of the world over time, so we have genetic continuity from 10,000 years ago to the present," said University of Illinois anthropology professor Ripan Malhi, who led the study with University of Chicago postdoctoral researcher John Lindo; Penn State University biology professor Michael DeGiorgio; Rosita Worl, the director of the Sealaska Heritage Institute in Juneau, Alaska; and University of Oklahoma anthropology professor Brian M. Kemp.

The findings, reported in the Proceedings of the National Academy of Sciences, also suggest that these early American peoples had a complex population history, the researchers report.

The new work comes on the heels of earlier studies of ancient Americans that focused on mitochondrial DNA, which occurs outside the nucleus of cells and is passed only from mothers to their offspring.

"Mitochondrial DNA just traces the maternal line -- your mother's mother's lineage -- so, you're missing information about all of these other ancestors," said Lindo, the first author on the paper. "We wanted to analyze the nuclear genome so we could get a better assessment of the population history of this region."

The team looked at genomic data from Shuká Káa (Tlingit for "Man Before Us"), an ancient individual whose remains -- found in a cave in southeastern Alaska -- date to about 10,300 years ago. They also analyzed the genomes of three more individuals from the nearby coast of British Columbia whose remains date to between 6,075 and 1,750 years ago.

"Interestingly, the mitochondrial type that Shuká Káa belonged to was also observed from another ancient skeleton dated to about 6,000 years ago," Kemp said. "It seems to disappear after that. The nuclear DNA suggests that this is probably not about population replacement, but rather chance occurrence through time. If a female has no children or only sons, the mitochondrial DNA is not passed to the next generation. As a male, Shuká Káa could not have passed on his own mitochondrial DNA; he must have had some maternal relatives that did so."

The researchers turned their attention to nuclear DNA, which offers a more comprehensive record of a person's ancestry.

"DNA from the mitochondria and Y chromosome provide unique yet sometimes conflicting stories, but the nuclear genome provides a more comprehensive view of past events," DeGiorgio said.

"The data suggest that there were multiple genetic lineages in the Americas from at least 10,300 years ago," Malhi said.

The descendants of some of those lineages are still living in the same region today, and a few are co-authors on the new study. Their participation is the result of a long-term collaboration between the scientists and several native groups who are embracing genomic studies as a way to learn from their ancestors, said Worl, who is Tlingit, Ch'áak' (Eagle) moiety of the Shangukeidí (Thunderbird) Clan from the Kawdliyaayi Hít (House Lowered From the Sun) in Klukwan, Alaska.

Read more at Science Daily

Bionic Leaf That ‘Bottles Sunlight’ Could Spur the Next Green Revolution

Harvard researchers have invented a so-called “bionic leaf” that produces fertilizer directly in farm soil, an innovation that could one day allow impoverished rural farmers in developing countries to make their own fertilizer on-site, significantly boosting crop yields.

The invention could be used to fight global hunger as populations expand in places like sub-Saharan Africa over the coming decades.

The researchers have already tapped their invention to grow radishes 50 percent larger than control crops raised without fertilizer, according to Dr. Daniel Nocera, who presented the findings at a press conference in San Francisco.

“I’m not saying this is an industry that’s ready to go next week,” Nocera told journalists during the annual meeting of the American Chemical Society. “I just wanted to find out if we could actually do it. And the answer is ‘Yes.’ Sometimes when you’re doing science, you just want to get to the top of the mountain to prove it can be done.”

Nocera’s current work stems from his earlier innovation unveiled six years ago: an artificial leaf that can break water down into hydrogen and oxygen using sunlight.

The new invention builds on that device. After splitting oxygen from hydrogen, it deploys a special bacteria that combines the hydrogen with carbon dioxide from the environment to create a bio-plastic. The bacteria then stores the bio-plastic as fuel internally.

“We’ve basically bottled sunlight in the form of this bio-plastic,” Nocera said.

The radishes on the right were grown with the help of a bionic leaf that produces fertilizer with bacteria, sunlight, water, and air.

Once the bio-plastic formed by the bacteria is placed in soil, it pulls nitrogen from the air to make ammonia, which acts as a fertilizing agent.

Advances in fertilizer played a key role in population growth during the 20th century, and commercial fertilizer now accounts for 30-50 percent of crop yields worldwide, according to various estimates.

Producing significant amounts of fertilizer typically requires large, expensive industrial facilities. In poor countries with underdeveloped infrastructure, there is a further need for distribution methods to transport the nutrient-rich substance to remote rural areas where subsistence farmers live.

“I’ve always felt the only importance of my research is, ‘Can I do the things that you already do in this society at large industrial scales with distribution systems, but in the back yard for the poor?’” Nocera said.

Read more at Discovery News

The Mystery of How Black Holes Collide and Merge Is Beginning to Unravel

An illustration of two supermassive black holes about to merge, with jets of superheated gas being emitted from their edges.

Last year, scientists announced that they had finally observed gravitational waves, the elusive and long sought-after ripples in the fabric of spacetime that were first posited by Albert Einstein. The waves came from a catastrophic event — the collision of two black holes located about 1.3 billion light years away from Earth — and the released energy undulated across the universe, much like ripples in a pond.

The detection by the upgraded Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO), along with two subsequent gravitational wave discoveries, confirmed a major prediction of Einstein’s 1915 general theory of relativity and heralded a new era in physics, allowing scientists to study the universe in a new way by using gravity instead of light.

But a fundamental question remains unanswered: How and why do black holes collide and merge?

In order for the black holes to merge, they must start out very close together by astronomical standards, no more than about a fifth of the distance between the Earth and the Sun. But only stars with very large masses can become black holes, and during the course of their lives, these stars expand to become even larger.  

A new study published in Nature Communications uses a model called COMPAS (Compact Object Mergers: Population Astrophysics and Statistics) in an attempt to answer how large binary stars that would eventually become black holes fit within a very small orbit. COMPAS allows the researchers to pursue a kind of “paleontology” for gravitational waves.

“A paleontologist, who has never seen a living dinosaur, can figure out how the dinosaur looked and lived from its skeletal remains,” said Ilya Mandel from the University of Birmingham in the UK, senior author of a paper, in a statement. “In a similar way, we can analyze the mergers of black holes, and use these observations to figure out how those stars interacted during their brief but intense lives."

What they found was that even two widely separated “progenitor” stars can interact when they expand, engaging in several episodes of mass transfer.

The researchers started by analyzing the three gravitational wave events that were detected by LIGO and attempted to see if all three black hole collisions evolved in the same way, which they call “classical isolated binary evolution via a common-envelope phase.”

It starts with two massive progenitor stars at quite wide separations. As the stars expand, once they come so close that they cannot escape each other's gravity, they begin to interact and engage in several episodes of mass transfer. This results in a very rapid, dynamically unstable event that envelops both stellar cores in a dense cloud of hydrogen gas.

“Ejecting this gas from the system takes energy away from the orbit,” the team said. “This brings the two stars sufficiently close together for gravitational-wave emission to be efficient, right at the time when they are small enough that such closeness will no longer put them into contact.”

It actually takes few million years to form two black holes, with a possible subsequent delay of billions of years before the black holes merge and form a single, larger black hole. But that merger event itself can be quick and violent.

The researchers said the simulations with COMPAS have also helped the team to understand the typical properties of the binary stars that can go on to form such pairs of merging black holes and the environments where this can happen.

For example, the team found that a merger of two black holes with significantly unequal masses would be a strong indication that the stars formed almost entirely from hydrogen and helium — called low-metallicity stars — with other elements contributing fewer than 0.1 percent of stellar matter (for comparison, this fraction is about 2 percent in our Sun). They were able to determine that all three events detected by LIGO could have formed in low-metallicity environments.

"The beauty of COMPAS is that it allows us to combine all of our observations and start piecing together the puzzle of how these black holes merge, sending these ripples in spacetime that we were able to observe at LIGO," said Simon Stevenson, a Ph.D. candidate at the University of Birmingham and the paper’s lead author.

Read more at Discovery News

Steppe migrant thugs pacified by Stone Age farming women

Corded ware vessel, an axe and two discs made of amber from an early male grave.

In an earlier study Professor Kristian Kristiansen from the University of Gothenburg in Sweden and Lundbeck Foundation Professor Eske Willerslev from the Centre for GeoGenetics at the University of Copenhagen, and their research teams, showed that the large demographic changes during the first part of the Bronze Age happened as a result of massive migrations of Yamnaya people from the Pontic-Caspian steppes into Neolithic Europe. They were also able to show that plague was widespread in both Europe and Central Asia at this time.

Now Professor Kristiansen and Professor Willerslev with co-authors reveal a more detailed view of the mechanism behind the emerging culture known as the Corded Ware Culture -- the result of the encounter between the Yamnaya and the Neolithic people. Professor Kristian Kristiansen says: "We are now for the first time able to combine results from genetics, strontium isotopes on mobility and diet, and historical linguistics on language change, to demonstrate how the integration process unfolded on the ground after the Yamnaya migrations from the steppe. In our grand synthesis we argue that Yamnaya migrants were predominantly males, who married women who came from neighbouring Stone Age farming societies" These Stone Age Neolithic societies were based on large farming communities reflected in their collective burial ritual often in big stone chambers, so called megaliths. Very different from the traditions of the incoming migrants.

The origin of the Yamnaya

The Yamnaya people originated on the Caspian steppes where they lived as pastoralists and herders, using wagons as mobile homes. From burial pits archaeologists have found extensive use of thick plant mats and felt covers. Their economy was based on meat, dairy products and fish, they were tall and rather healthy with little caries in their teeth. No agriculture is documented. Barrows were aligned in groups forming lines in the landscape to mark seasonal routes and after death diseased people were put into individual graves under small family barrows. Their burial ritual thus embodied a new perception of the individual and of small monogamous family groups as the foundation of society. The continent encountered by the Yamnaya people around 3000 BC had seen a decline in the agrarian Stone Age societies, thereby allowing space for incoming migrants. This decline was probably the result of a widespread plague from Siberia to the Baltic.

"The disease dynamic here may have been comparable to the European colonization process in America after Christopher Columbus," says Kristiansen. "Perhaps Yamnaya brought plague to Europe and caused a massive collapse in the population."

"Black Youth" as migrating males and their marriage to Neolithic women

In the new synthesis article, Kristiansen and colleagues argue for a dominance of males during the early phase after the migrations, and correspond to the old Indo-European mythology of later times. These sources talk about war-bands of youths -- called "Black Youth" -- who were employed in pioneer migrations as a dynamic force. Evidence from strontium isotopic analyses, published in 2016 by Kristiansen together with Douglas Price and Karl Goran Sjogren, showed that a majority of the women in Corded Ware burials in south Germany were non-locals who had married in from Neolithic societies, since they had a Neolithic diet in their childhood. These results now form part of the new synthesis. Professor Kristian Kristiansen says: "Existing archaeological evidence of a strong 90% male dominance in the early phase of the Corded Ware/Single Grave Culture settlement in Jutland, Denmark, and elsewhere can now be explained by the old Indo-European tradition of war bands of young males who did not have any inheritance to look forward to. Therefore they were probably more willing to make a career as migrating war bands."

These Neolithic women also brought new knowledge of pottery production, and started to imitate pottery containers made of wood from the Yamnaya migrants. In this way a new pottery culture was created called Corded Ware, because of the cord impressions around the neck of the pots. They were made for beer drinking, and the new migrants also learned how to grow barley from the in-married Neolithic women in order to produce beer.

Rapid genetic changeover from Neolithic to Corded Ware cultures after 3000 BC

Eske Willerslev undertook the ancient DNA analyses together with Morten Allentoft and Martin Sikora. Professor Willerslev says:

"In our big Bronze Age study, published in 2015 we were astonished to see how strong and fast the genetic changeover was from the Neolithic to the Corded Ware. There was a heavy reduction of Neolithic DNA in temperate Europe, and a dramatic increase of the new Yamnaya genomic component that was only marginally present in Europe prior to 3000 BC. Moreover, the apparent abruptness with which this change occurred indicates that it was a large-scale migration event, rather than a slow periodic inflow of people."

New words and new Proto-Germanic dialect

The Yamnaya brought the Indo-European languages into Bronze Age Europe, but as herders, they did not have words for crops or cultivation, unlike the Neolithic farmers. As the Corded Ware Culture developed it adopted words related to farming from the indigenous Neolithic people, which they were admixing with. Guus Kroonen, a historical linguist, was able to demonstrate that these new words did not belong to the original Indo-European languages. Therefore it was possible to conclude that the Neolithic people were not speaking an Indo-European language, as did the Yamnaya migrants. Thus, the process of genetic and cultural admixture was accompanied by a process of language admixture, creating the foundations for later Germanic languages, termed Proto-Germanic.

Read more at Science Daily