More than 50,000 years ago, a Neanderthal woman and a Denisovan man had sex, and a few months later she gave birth to a girl . Many centuries later, in a Siberian cave next to the Altai Mountains, the bones were found that left this half-breed woman who was about 13 years old at his death .
It has been known for almost a decade that Neanderthals, Denisovans and
modern humans under certain circumstances had offspring, but a son of a mixed couple was never found .
Today, the magazine Nature published the genome of the first of these people . A team from Viviane Slon and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig analyzed the DNA extracted from a bone fragment of the young woman and concluded that the mother was Neanderthal and Denisovan Father . The first connects the adolescent with the lineage of a well-known species, to which the first known artistic expressions are attributed and which have left their bones and tools throughout Europe. Her father makes her the descendant of a much more mysterious group, known only from the genetic analysis of small bone fragments found only in the Russian Denisova Cave.
The genomes of the two species, also sequenced by Pääbo, and his collaborators indicate that they separated more than 390,000 years ago. However, in the areas where both species shared a common border, they were able to continue breeding in time. "Although we do not yet know the anatomy of denisovanos [solo se han encontrado fragmentos de huesos y dientes]I believe that they would not be anatomically very different, although they would not be the same," explains Juan Luis Arsuaga, co-director of Atapuerca. " The Denisovans would be something like the Asian version of the Neanderthals ," he adds.
Since genetic analysis allowed us to reconstruct the sex life of primitive man, it turned out that there were occasional relationships that divided the world tens of thousands of years ago. The genome of Denisova 1
1 or Denny, when the girl was baptized, shows
that her parents' relationship was not the first cross between species
of her family . The father also had Neanderthals among his ancestors.
The researcher at the Max Planck Institute for Evolutionary Anthropology, Vivian Slon, first author of the study
Relations between these two closely related species are not accidental. Modern humans repeatedly copied with Neanderthals for at least 100,000 years and today, all inhabitants of the planet, except Sub-Saharan, have in our genome DNA of this extinct species . The same thing happens with Denisovanos. Although they have long been extinct, they have left some of their genes between Asians and the ocean, and they also have traces of fornication in their genome with an archaic human species that split off from the human evolutionary line more than a million years ago] Arsuaga tries to imagine the circumstances under which these relationships between species can occur, and to remember what other mammals are doing. "The fact that wolves and jackals or two types of bears exchange genes is relatively common in the boundaries of the territories they occupy," he says. But these animals do not usually merge their groups. "I do not believe that a group of Neanderthals and one of Denisovans have joined together into a single group and there were these crosses," explains the paleoanthropologist. Rather, they are isolated individuals who are excluded from the group and have no access to females of their species. "A marginal wolf in California or a young can breed with a female coyote they find," he says.
The possible relationship between the marginalized Denisovano and a western-born Neanderthal was reflected in the Denisova girl. Although it was known that both species had offspring, it is surprising. " I never thought we would be lucky enough to find a direct descendant of the two groups ," says Slon. Pääbo considers the finding unlikely and believes that "they may not have had many opportunities to meet, but they must have copulated frequently, much more than previously thought."
Carles Lalueza, researcher at the Institute of Evolutionary Biology From Barcelona, he also sees "really surprising" that a first-generation hybrid was found. "This may indicate that the crosses were common, but we do not know, in part because all Denisovans come from the same cave," he says. Although he points out that "what really revolutionary would be to find another Denisovan in another place because we may study a marginal populace."
The unknowns around this stage of humanity, when people had not yet
imposed their law. At least three enormously intelligent species divide
planets and rivers, they are abundant. Works such as those published today are evidence that science can open unexpected windows into the past .
In 2006, Bruce Lahn of the University of Chicago suggested that
Neanderthals and humans shared genes about 40,000 years ago. As he told
at the time, the magazines Science and Nature
refused to publish the work because they believed that crossing was
impossible. In just a decade, this vision of Pleistocene sex and its
consequences has been turned upside down.
Today, the magazine Nature published the genome of the first of these people . A team from Viviane Slon and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig analyzed the DNA extracted from a bone fragment of the young woman and concluded that the mother was Neanderthal and Denisovan Father . The first connects the adolescent with the lineage of a well-known species, to which the first known artistic expressions are attributed and which have left their bones and tools throughout Europe. Her father makes her the descendant of a much more mysterious group, known only from the genetic analysis of small bone fragments found only in the Russian Denisova Cave.
The genomes of the two species, also sequenced by Pääbo, and his collaborators indicate that they separated more than 390,000 years ago. However, in the areas where both species shared a common border, they were able to continue breeding in time. "Although we do not yet know the anatomy of denisovanos [solo se han encontrado fragmentos de huesos y dientes]I believe that they would not be anatomically very different, although they would not be the same," explains Juan Luis Arsuaga, co-director of Atapuerca. " The Denisovans would be something like the Asian version of the Neanderthals ," he adds.
Since genetic analysis allowed us to reconstruct the sex life of primitive man, it turned out that there were occasional relationships that divided the world tens of thousands of years ago. The genome of Denisova 1
The researcher at the Max Planck Institute for Evolutionary Anthropology, Vivian Slon, first author of the study
Relations between these two closely related species are not accidental. Modern humans repeatedly copied with Neanderthals for at least 100,000 years and today, all inhabitants of the planet, except Sub-Saharan, have in our genome DNA of this extinct species . The same thing happens with Denisovanos. Although they have long been extinct, they have left some of their genes between Asians and the ocean, and they also have traces of fornication in their genome with an archaic human species that split off from the human evolutionary line more than a million years ago] Arsuaga tries to imagine the circumstances under which these relationships between species can occur, and to remember what other mammals are doing. "The fact that wolves and jackals or two types of bears exchange genes is relatively common in the boundaries of the territories they occupy," he says. But these animals do not usually merge their groups. "I do not believe that a group of Neanderthals and one of Denisovans have joined together into a single group and there were these crosses," explains the paleoanthropologist. Rather, they are isolated individuals who are excluded from the group and have no access to females of their species. "A marginal wolf in California or a young can breed with a female coyote they find," he says.
The possible relationship between the marginalized Denisovano and a western-born Neanderthal was reflected in the Denisova girl. Although it was known that both species had offspring, it is surprising. " I never thought we would be lucky enough to find a direct descendant of the two groups ," says Slon. Pääbo considers the finding unlikely and believes that "they may not have had many opportunities to meet, but they must have copulated frequently, much more than previously thought."
Carles Lalueza, researcher at the Institute of Evolutionary Biology From Barcelona, he also sees "really surprising" that a first-generation hybrid was found. "This may indicate that the crosses were common, but we do not know, in part because all Denisovans come from the same cave," he says. Although he points out that "what really revolutionary would be to find another Denisovan in another place because we may study a marginal populace."
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B.
Mum’s a Neanderthal, Dad’s a Denisovan: First discovery of an ancient-human hybrid
Denny inherited one set of chromosomes from her Neanderthal ancestors, depicted in this model.Credit: Christopher Rynn/University of Dundee
“To find a first-generation person of mixed ancestry from these groups is absolutely extraordinary,” says population geneticist Pontus Skoglund at the Francis Crick Institute in London. “It’s really great science coupled with a little bit of luck.”
The team, led by palaeogeneticists Viviane Slon and Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, conducted the genome analysis on a single bone fragment recovered from Denisova Cave in the Altai Mountains of Russia. This cave lends its name to the ‘Denisovans’, a group of extinct humans first identified on the basis of DNA sequences from the tip of a finger bone discovered2 there in 2008. The Altai region, and the cave specifically, were also home to Neanderthals.
Given the patterns of genetic variation in ancient and modern humans, scientists already knew that Denisovans and Neanderthals must have bred with each other — and with Homo sapiens (See 'Tangled Tree'). But no one had previously found the first-generation offspring from such pairings, and Pääbo says that he questioned the data when his colleagues first shared them. “I thought they must have screwed up something.” Before the discovery of the Neanderthal–Denisovan individual, whom the team has affectionately named Denny, the best evidence for so close an association was found in the DNA of a Homo sapiens specimen who had a Neanderthal ancestor within the previous 4–6 generations3.
Ancestry revealed
Pääbo’s team first uncovered Denny’s remains several years ago, by looking through a collection of more than 2,000 unidentified bone fragments for signs of human proteins. In a 2016 paper4, they used radiocarbon dating to determine that the bone belonged to a hominin who lived more than 50,000 years ago (the upper limit of the dating technique; subsequent genetic analysis has put the specimen at around 90,000 years old, according to Pääbo). They then sequenced the specimen’s mitochondrial DNA — the DNA found inside cells’ energy converters — and compared that data to sequences from other ancient humans. This analysis showed that the specimen’s mitochondrial DNA came from a Neanderthal.But this was only half of the picture. Mitochondrial DNA is inherited from the mother and represents just a single line of inheritance, leaving the identity of the father and the individual’s broader ancestry unknown.
A bone fragment was sequenced for its genome.Credit: Thomas Higham/University of Oxford
With equal amounts of Denisovan and Neanderthal DNA, the specimen seemed to have one parent from each hominin group. But there was another possibility: Denny's parents could have belonged to a population of Denisovan–Neanderthal hybrids.
A fascinating genome
To work out which of these options was more likely, the researchers examined sites in the genome where Neanderthal and Denisovan genetics differ. At each of these locations, they compared fragments of Denny's DNA to the genomes of the two ancient hominins. In more than 40% of cases, one of the DNA fragments matched the Neanderthal genome, whereas the other matched that of a Denisovan, suggesting that she had acquired one set of chromosomes from a Neanderthal and the other from a Denisovan. That made it clear that Denny was the direct offspring of two distinct humans, says Pääbo. “We’d almost caught these people in the act.”The results convincingly demonstrate that the specimen is indeed a first-generation hybrid, says Kelley Harris, a population geneticist at the University of Washington in Seattle who has studied hybridization between early humans and Neanderthals. Skoglund agrees: “It’s a really clear-cut case,” he says. “I think it’s going to go into the textbooks right away.”
Harris says that sexual encounters between Neanderthals and Denisovans might have been quite common. “The number of pure Denisovan bones that have been found I can count on one hand,” she says — so the fact that a hybrid has already been discovered suggests that such offspring could have been widespread. This raises another interesting question: if Neanderthals and Denisovans mated frequently, why did the two hominin populations remain genetically distinct for several hundred-thousand years? Harris suggests that Neanderthal–Denisovan offspring could have been infertile or otherwise biologically unfit, preventing the two species from merging.
Neanderthal-Denisovan pairings could also have had some advantages, even if there were other costs, says Chris Stringer, a palaeoanthropologist at the Natural History Museum in London. Neanderthals and Denisovans were less genetically diverse than modern humans, and so interbreeding might have provided a way of “topping up” their genomes with a bit of extra genetic variation, he says. The study also raises questions over how matings between different human groups happened, says Stringer — for example, whether or not they were consensual. A more detailed account of the gene flow between Neanderthals and Denisovans in the future might offer hints into ancient human behaviour.
Missed connections
Pääbo agrees that Neanderthals and Denisovans would have readily bred with each other when they met - but he thinks that those encounters were rare. Most Neanderthal remains have been found across western Eurasia, whereas Denisovans have so far been discovered only in their eponymous Siberian cave. Although the two groups’ home turf overlapped in the Altai Mountains and possibly elsewhere, these areas would have been sparsely populated. “I think any Neanderthal that lived west of the Urals would never ever meet a Denisovan in their life,” Pääbo says, referring to the mountain range that slices through western Russia and Kazakhstan.
Denny's remains were discovered in Denisova Cave in southern Siberia.Credit: Bence Viola/Max Planck Institute for Evolutionary Anthropology
The Croatian Neanderthal died died much more recently than Denny — about 55,000 years ago — while the Neanderthal from Denisova Cave is around 120,000 years old. That leaves two possibilities to explain the ancestry of Denny's mother: either a population of European Neanderthals came east to the Altai Mountains and partly replaced the region’s Neanderthals before the hybrid was born, or a group of Neanderthals could have left the Altai Mountains for Europe sometime after Denny’s birth. Either way, says Harris, Neanderthals “didn’t just stay in one place for thousands of years”.
With a Neanderthal mother and a Denisovan father, what should we call the new specimen? “We shy away a little from the word ‘hybrid’,” says Pääbo. The term implies that the two groups are discrete species of human, whereas in reality the boundaries between them are blurry — as the new study shows. Defining a species in the natural world is not always clear-cut, says Harris, and it’s interesting to see long-running debates about how to categorize organisms start to be applied to humans.
Whatever scientists decide to call Denny, Skoglund says he would have loved to be able to meet her. “It’s probably the most fascinating person who’s ever had their genome sequenced.”
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C.Saga of early humans etched in DNA of mixed-species child
 Paris (AFP) - Denny was an inter-species love child. Her mother was a Neanderthal, but her father was Denisovan, a distinct species of primitive human that also roamed the Eurasian continent 50,000 years ago, scientists reported Wednesday in the journal Nature. Nicknamed by Oxford University scientists, Denisova 11 -- her official name -- was at least 13 when she died, for reasons unknown. "There was earlier evidence of interbreeding between different hominin, or early human, groups," said lead author Vivian Slon, a researcher at the Max Planck Institute for Evolutionary Anthropology. "But this is the first time that we have found a direct, first-generation offspring," she told AFP. Denny's surprising pedigree was unlocked from a bone fragment unearthed in 2012 by Russian archeologists at the Denisova Cave in the Altai Mountains of Siberia. Analysis of the bone's DNA left no doubt: the chromosomes were a 50-50 mix of Neanderthal and Denisovan, two distinct species of early humans that split apart between 400,000 to 500,000 years ago. "I initially thought that they must have screwed up in the lab," said senior author and Max Planck Institute professor Svante Paabo, who identified the first Denisovan a decade ago at the same site. Worldwide, fewer than two dozen early human genomes from before 40,000 years ago -- Neanderthal, Denisovan, Homo sapiens -- have been sequenced, and the chances of stumbling on a half-and-half hybrid seemed vanishingly small. Or not. - Inter-species hanky-panky - "The very fact that we found this individual of mixed Neanderthal and Denisovan origins suggests that they interbred much more often than we thought," said Slon. Paabo agreed: "They must have quite commonly had kids together, otherwise we wouldn't have been this lucky." A 40,000 year-old Homo sapiens with a Neanderthal ancestor a few generations back, recently found in Romania, also bolsters this notion. But the most compelling evidence that inter-species hanky-panky in Late Pleistocene Eurasia may not have been that rare lies in the genes of contemporary humans. About two percent of DNA in non-Africans across the globe today originate with Neanderthals, earlier studies have shown. Denisovan remnants are also widespread, though less evenly. "We find traces of Denisovan DNA -- less than one percent -- everwhere in Asia and among native Americans," said Paabo. "Aboriginal Australians and people in Papua New Guinea have about five percent." Taken together, these facts support a novel answer to the hotly debated question of why Neanderthals -- which had successfully spread across parts of western and central Europe -- disappeared some 40,000 years ago. Up to now, their mysterious demise has been blamed on disease, climate change, genocide at the hands of Homo sapiens, or some combination of the above. But what if our species -- arriving in waves from Africa -- overwhelmed Neanderthals, and perhaps Denisovans, with affection rather than aggression? - Conquered or absorbed? - "Part of the story of these groups is that they may simply have been absorbed by modern populations," said Paabo. "The modern humans were more numerous, and the other species might have been incorporated." Recent research showing that Neanderthals were not, in fact, knuckle-dragging brutes makes this scenario all the more plausible. Our genetic cousins executed sophisticated hunting strategies in groups; made fires, tools, clothing and jewellery; and buried their dead with symbolic ornaments. They painted animal frescos on cave walls at least 64,000 years ago, well before most Homo sapiens arrived in Europe. Far less is known about Denisovans, but they may have suffered a similar fate. Paabo established their existence with an incomplete finger bone and two molars dated to some 80,000 years ago. Among their genetic legacy to some modern humans is a variant of the gene EPAS1 that makes it easier for the body to access oxygen by regulating the production of haemoglobin, according to a 2014 study. Nearly 90 percent of Tibetans have this precious variant, compared with only nine percent of Han Chinese, the dominant -- and predominantly lowland -- ethnic group in China. Neanderthals and Denisovans might have intermingled even more but for the fact that the former settled mostly in Europe, and the latter in central and East Asia, the researchers speculated. COVFEFE!!  “Nothing in the world is more dangerous than a sincere ignorance and conscientious stupidity.”---Martin Luther King, Jr. Revelations of truth undermine a foundation of belief built on lies.---Sev If our answers scare you, maybe you should stop asking frightening questions.---ChicagoRJ |
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