Neandertal admixture in Eurasians thread

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A ground-breaking new study on DNA recovered from a fossil of one of the earliest known Europeans -- a man who lived 36,000 years ago in Kostenki, western Russia -- has shown that the earliest European humans' genetic ancestry survived the Last Glacial Maximum: the peak point of the last ice age.

The study also uncovers a more accurate timescale for when humans and Neanderthals interbred, and finds evidence for an early contact between the European hunter-gatherers and those in the Middle East -- who would later develop agriculture and disperse into Europe about 8,000 years ago, transforming the European gene pool.

Scientists now believe Eurasians separated into at least three populations earlier than 36,000 years ago: Western Eurasians, East Asians and a mystery third lineage, all of whose descendants would develop the unique features of most non-African peoples -- but not before some interbreeding with Neanderthals took place.

Led by the Centre for GeoGenetics at the University of Copenhagen, the study was conducted by an international team of researchers from institutions including the University of Cambridge's Departments of Archaeology and Anthropology, and Zoology, and is published today in the journal Science.

By cross-referencing the ancient man's complete genome -- the second oldest modern human genome ever sequenced -- with previous research, the team discovered a surprising genetic "unity" running from the first modern humans in Europe, suggesting that a 'meta-population' of Palaeolithic hunter-gatherers with deep shared ancestry managed to survive through the Last Glacial Maximum and colonise the landmass of Europe for more than 30,000 years.

While the communities within this overarching population expanded, mixed and fragmented during seismic cultural shifts and ferocious climate change, this was a "reshuffling of the same genetic deck" say scientists, and European populations as a whole maintained the same genetic thread from their earliest establishment out of Africa until Middle Eastern populations arrived in the last 8,000 years, bringing with them agriculture and lighter skin colour.

"That there was continuity from the earliest Upper Palaeolithic to the Mesolithic, across a major glaciation, is a great insight into the evolutionary processes underlying human success," said co-author Dr Marta Mirazón Lahr, from Cambridge's Leverhulme Centre for Human Evolutionary Studies (LCHES).

"For 30,000 years ice sheets came and went, at one point covering two-thirds of Europe. Old cultures died and new ones emerged -- such as the Aurignacian and the Grevettian -- over thousands of years, and the hunter-gatherer populations ebbed and flowed. But we now know that no new sets of genes are coming in: these changes in survival and cultural kit are overlaid on the same biological background," Mirazón Lahr said. "It is only when famers from the Near East arrived about 8,000 years ago that the structure of the European population changed significantly."

The Kostenki genome also contained, as with all people of Eurasia today, a small percentage of Neanderthal genes, confirming previous findings which show there was an 'admixture event' early in the human colonisation Eurasia: a period when Neanderthals and the first humans to leave Africa for Europe briefly interbred.

The new study allows scientists to closer estimate this 'event' as occurring around 54,000 years ago, before the Eurasian population began to separate. This means that, even today, anyone with a Eurasian ancestry -- from Chinese to Scandinavian and North American -- has a small element of Neanderthal DNA.

However, despite Western Eurasians going on to share the European landmass with Neanderthals for another 10,000 years, no further periods of interbreeding occurred.

"Were Neanderthal populations dwindling very fast? Did modern humans still encounter them? We were originally surprised to discover there had been interbreeding. Now the question is, why so little? It's an extraordinary finding that we don't understand yet," said co-author Professor Robert Foley, also from LCHES.

Unique to the Kostenki genome is a small element it shares with people who live in parts of the Middle East now, and who were also the population of farmers that arrived in Europe about 8,000 years ago and assimilated with indigenous hunter-gatherers. This early contact is surprising, and provides the first clues to a hereto unknown lineage that could be as old as -- or older than -- the other major Eurasian genetic lines. These two populations must have interacted briefly before 36,000 years ago, and then remained isolated from each other for tens of millennia.

"This element of the Kostenki genome confirms the presence of a yet unmapped major population lineage in Eurasia. The population separated early on from ancestors of other Eurasians, both Europeans and Eastern Asians," said Andaine Seguin-Orlando from the Centre for GeoGenetics in Copenhagen.

Mirazón Lahr points out that, while Western Eurasia was busy mixing as a 'meta-population', there was no interbreeding with these mystery populations for some 30,000 years -- meaning there must have been some kind of geographic barrier for millennia, despite the fact that Europe and the Middle East seem, for us at least, to be so close geographically. But the Kostenki genome not only shows the existence of these unmapped populations, but that there was at least one window of time when whatever barrier existed became briefly permeable.

"This mystery population may have remained small for a very long time, surviving in refugia in areas such as the Zagros Mountains of Iran and Iraq, for example," said Mirazón Lahr. "We have no idea at the moment where they were for those first 30,000 years, only that they were in the Middle East by the end of the ice age, when they invented agriculture."

Lead author and Lundbeck Foundation Professor Eske Willerslev added: "This work reveals the complex web of population relationships in the past, generating for the first time a firm framework with which to explore how humans responded to climate change, encounters with other populations, and the dynamic landscapes of the ice age."
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http://www.sciencedaily.com/releases/2014/11/141106143719.htm
 
Very interesting, thanks. Fascinating stuff.
 
Compton_effect said:
they actually theorise that we inherited diabetes from Neandertal Man.
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yup,
so much for hybrid vigour:

http://www.business-standard.com/ar...herited-from-neanderthals-113122600284_1.html


hybrid vigour
The increased vigor or general health, resistance to disease, and other superior qualities that are often manifested in hybrid organisms, especially plants and animals
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read this: http://www.thewildlifenews.com/2012...-not-be-as-fit-as-those-without-cattle-genes/
 
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Were Neanderthals a sub-species of modern humans? New research says no

neanderthal.jpg
A Neanderthal skeleton, left, compared with a modern human skeleton


18 Nov 2014

In an extensive, multi-institution study led by SUNY Downstate Medical Center, researchers have identified new evidence supporting the growing belief that Neanderthals were a distinct species separate from modern humans (Homo sapiens), and not a subspecies of modern humans.

The study looked at the entire nasal complex of Neanderthals and involved researchers with diverse academic backgrounds. Supported by funding from the National Science Foundation and the National Institutes of Health, the research also indicates that the Neanderthal nasal complex was not adaptively inferior to that of modern humans, and that the Neanderthals' extinction was likely due to competition from modern humans and not an inability of the Neanderthal nose to process a colder and drier climate.

Samuel Márquez, PhD, associate professor and co-discipline director of gross anatomy in SUNY Downstate's Department of Cell Biology, and his team of specialists published their findings on the Neanderthal nasal complex in the November issue of The Anatomical Record, which is part of a special issue on The Vertebrate Nose: Evolution, Structure, and Function (now online).

They argue that studies of the Neanderthal nose, which have spanned over a century and a half, have been approaching this anatomical enigma from the wrong perspective. Previous work has compared Neanderthal nasal dimensions to modern human populations such as the Inuit and modern Europeans, whose nasal complexes are adapted to cold and temperate climates.

However, the current study joins a growing body of evidence that the upper respiratory tracts of this extinct group functioned via a different set of rules as a result of a separate evolutionary history and overall cranial bauplan (bodyplan), resulting in a mosaic of features not found among any population of Homo sapiens. Thus Dr. Márquez and his team of paleoanthropologists, comparative anatomists, and an otolaryngologist have contributed to the understanding of two of the most controversial topics in paleoanthropology - were Neanderthals a different species from modern humans and which aspects of their cranial morphology evolved as adaptations to cold stress.

"The strategy was to have a comprehensive examination of the nasal region of diverse modern human population groups and then compare the data with the fossil evidence. We used traditional morphometrics, geometric morphometric methodology based on 3D coordinate data, and CT imaging," Dr. Márquez explained.

Anthony S. Pagano, PhD, anatomy instructor at NYU Langone Medical Center, a co-author, traveled to many European museums carrying a microscribe digitizer, the instrument used to collect 3D coordinate data from the fossils studied in this work, as spatial information may be missed using traditional morphometric methods. "We interpreted our findings using the different strengths of the team members," Dr. Márquez said, "so that we can have a 'feel' for where these Neanderthals may lie along the modern human spectrum."

Co-author William Lawson, MD, DDS, vice-chair and the Eugen Grabscheid research professor of otolaryngology and director of the Paleorhinology Laboratory of the Icahn School of Medicine at Mount Sinai, notes that the external nasal aperture of the Neanderthals approximates some modern human populations but that their midfacial prognathism (protrusion of the midface) is startlingly different. That difference is one of a number of Neanderthal nasal traits suggesting an evolutionary development distinct from that of modern humans. Dr. Lawson's conclusion is predicated upon nearly four decades of clinical practice, in which he has seen over 7,000 patients representing a rich diversity of human nasal anatomy.

Distinguished Professor Jeffrey T. Laitman, PhD, also of the Icahn School of Medicine and director of the Center for Anatomy and Functional Morphology, and Eric Delson, PhD, director of the New York Consortium in Evolutionary Primatology or NYCEP, are also co-authors and are seasoned paleoanthropologists, each approaching their fifth decade of studying Neanderthals. Dr. Delson has published on various aspects of human evolution since the early 1970's.

Dr. Laitman states that this article is a significant contribution to the question of Neanderthal cold adaptation in the nasal region, especially in its identification of a different mosaic of features than those of cold-adapted modern humans. Dr. Laitman's body of work has shown that there are clear differences in the vocal tract proportions of these fossil humans when compared to modern humans. This current contribution has now identified potentially species-level differences in nasal structure and function.
Dr. Laitman said, "The strength of this new research lies in its taking the totality of the Neanderthal nasal complex into account, rather than looking at a single feature. By looking at the complete morphological pattern, we can conclude that Neanderthals are our close relatives, but they are not us."

Ian Tattersall, PhD, emeritus curator of the Division of Anthropology at the American Museum of Natural History, an expert on Neanderthal anatomy and functional morphology who did not participate in this study, stated, "Márquez and colleagues have carried out a most provocative and intriguing investigation of a very significant complex in the Neanderthal skull that has all too frequently been overlooked." Dr. Tattersall hopes that "with luck, this research will stimulate future research demonstrating once and for all that Homo neanderthalensis deserves a distinctive identity of its own."
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http://phys.org/news/2014-11-neanderthals-sub-species-modern-humans.html#jCp



Bye, bye to:
a biological species is a group of individuals which can breed together .
 
Nerfherder said:
Well.... we dominated the Neanderthal they died and we survived.

and we all have a bit of Neanderthal DNA inside us so that means that the hybrids did survive. Just the ones with more human DNA did better.
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We had nothing to do with it. Climate change was the main factor. Neanderthal man was top of the food chain. But then the weather patterns started to change, and global temperatures rose. They were an apex predator, stocky build, adapted to the cold, but because of that needed to use a lot of energy. But when the last ice age ended and it became warmer, their prey started to become less.

Homo-Sapien Man was from the African continent, where it had been warmer, and food more difficult to find - so much more efficient and of a slimmer build.

Neanderthal Man did not stand a chance.
 
Compton_effect said:
Just goes to show. Men will stick it in anything.
But seriously - they actually theorise that we inherited diabetes from Neandertal Man.
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That makes no sense. Then Africans would not have diabetes at all.

Inherited a greater risk of developing diabetes? Perhaps that makes a bit more sense.
 
"The AGVP has provided interesting clues about ancient populations in Africa that pre-dated the Bantu expansion," (see, blacks aren't indigenous people to Africa ) says Dr Manjinder Sandhu, lead senior author from the Wellcome Trust Sanger Institute, UK and the Department of Medicine, University of Cambridge. "To better understand the genetic landscape of ancient Africa we will need to study modern genetic sequences from previously under-studied African populations, along with ancient DNA from archaeological sources."
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So they are basically saying that the Khoi san people are a completely different race to the Nguni people.

I can believe that.
 
Higher Levels of Neanderthal Ancestry in East Asians Than in Europeans

Neanderthals were a group of archaic hominins that occupied most of Europe and parts of Western Asia from roughly 30-300 thousand years ago (Kya). They coexisted with modern humans during part of this time. Previous genetic analyses that compared a draft sequence of the Neanderthal genome with genomes of several modern humans concluded that Neanderthals made a small (1-4%) contribution to the gene pools of all non-African populations. This observation was consistent with a single episode of admixture from Neanderthals into the ancestors of all non-Africans when the two groups coexisted in the Middle East 50-80 Kya.

We examined the relationship between Neanderthals and modern humans in greater detail by applying two complementary methods to the published draft Neanderthal genome and an expanded set of high-coverage modern human genome sequences. We find that, consistent with the recent finding of Meyer et al. (2012), Neanderthals contributed more DNA to modern East Asians than to modern Europeans.

Furthermore we find that the Maasai of East Africa have a small but significant fraction of Neanderthal DNA.

Because our analysis is of several genomic samples from each modern human population considered, we are able to document the extent of variation in Neanderthal ancestry within and among populations.

Our results combined with those previously published show that a more complex model of admixture between Neanderthals and modern humans is necessary to account for the different levels of Neanderthal ancestry among human populations. In particular, at least some Neanderthal-modern human admixture must postdate the separation of the ancestors of modern European and modern East Asian populations.
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http://www.genetics.org/content/early/2013/02/04/genetics.112.148213



Neanderthals interbred for longer with East Asian humans, DNA reveals
Scientists say Neanderthals and humans may have interbred multiple times
People in East Asia carry 15 to 30% more Neanderthal DNA than Europeans
They say Europeans appear to have interbred on just one occasion
But the ancestors of East Asians may have interbred for a second time
It suggests Neanderthals spread far further east than originally thought
Their remains are concentrated in Europe and as far east as central Asia
Experts say Neanderthals in the East may have outlived those in Europe
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read more at
http://www.dailymail.co.uk/sciencet...nger-modern-humans-east-Asia-DNA-reveals.html
 
Bull****. We did not evolve from sub-humans.
 
They say that the Ashkenazi Jews who come from Khazaria, which is dead center of the Neanderthal range, have the purest Neanderthal blood due to their religion precluding them from mixing with others. They are quite intelligent people.
 
Could Interbreeding Between Humans and Neanderthals Have Led to an Enhanced Human Brain?


Might mating between an ancient human and a Neanderthal - perhaps occurring in only a single instance - have introduced a gene variant into the human population that enhanced human brain function?

That question is at the heart of a new study by researchers at the Howard Hughes Medical Institute and the University of Chicago.

The new research, which was published online during the week of November 6, 2006, in the early edition of the Proceedings of the National Academy of Sciences (PNAS), suggests that human evolution was not just a matter of spontaneous advantageous mutations arising within the human lineage. Human evolution may also have been influenced by interbreeding with other Homo species, which introduced gene variants, known as alleles, that are beneficial to human reproductive fitness, said the study's senior author Bruce T. Lahn, a Howard Hughes Medical Institute researcher at the University of Chicago.

"By no means do these findings constitute definitive proof that a Neanderthal was the source of the original copy of the D allele. However, our evidence shows that it is one of the best candidates." - Bruce T. Lahn


The scientists said they have developed the most robust genetic evidence to date that suggests humans and Neanderthals interbred when they existed together thousands of years ago. The interbreeding hypothesis contrasts with at least one prominent theory that posits that no interbreeding occurred when the two species encountered one another.

Lahn collaborated on the studies with Patrick D. Evans, Nitzan Mekel-Bobrov, Eric J. Vallender and Richard R. Hudson, all of the University of Chicago.

In their studies, Lahn and his colleagues performed a detailed statistical analysis of the DNA sequence structure of the gene microcephalin, which is known to play a role in regulating brain size in humans. Mutations in the human gene cause development of a much smaller brain, a condition called microcephaly.

Earlier studies by Lahn's group yielded evidence that the microcephalin gene has two distinct classes of alleles. One class, called the D alleles, is comprised of a group of alleles with rather similar DNA sequences. The other class is called the non-D alleles. Lahn and colleagues previously showed that all modern copies of the D alleles arose from a single progenitor copy about 37,000 years ago, which then increased in frequency rapidly and are now present in about 70 percent of the world's population.
This rapid rise in frequency indicates that the D alleles underwent positive selection in the recent history of humans. This means that these alleles conferred a fitness advantage on those who possessed one of them such that these people had slightly higher reproductive success than people who didn't possess the alleles, said Lahn.

The estimate that all modern copies of the D alleles descended from a single progenitor copy about 37,000 years ago is based on the measurement of sequence difference between different copies of the D alleles. As a copy of a gene is passed from one generation to the next, mutations are introduced at a steady rate, such that a certain number of generations later, the descendent copies of the gene would on average vary from one another in DNA sequence by a certain amount. The greater the number of the generations, the more DNA sequence difference there would be between two descendent copies, said Lahn. The amount of sequence difference between different copies of a gene can therefore be used to estimate the amount of evolutionary time that has elapsed since the two copies descended from their common progenitor.

In the new studies reported in PNAS, the researchers performed detailed sequence comparisons between the D alleles and the non-D alleles of microcephalin. The scientists determined that these two classes of alleles have likely evolved in two separate lineages for about 1.1 million years -- with the non-D alleles having evolved in the Homo sapiens lineage and the D alleles having evolved in an archaic, and now extinct, Homo lineage. Then, about 37,000 years ago, a copy of the D allele crossed from the archaic Homo lineage into humans, possibly by interbreeding between members of the two populations. This copy subsequently spread in humans from a single copy when it first crossed into humans to an allele that is now present in an estimated 70 percent of the population worldwide today.

The estimate of 1.1 million years that separates the two lineages is based on the amount of sequence difference between the D and the non-D alleles. Although the identity of this archaic Homo lineage is yet to be determined, the researchers argue that a likely candidate is the Neanderthals. The 1.1 million year separation between humans and this archaic Homo species is roughly consistent with previous estimates of the amount of evolutionary time separating the Homo sapiens lineage and the Neanderthal lineage, said Lahn. Furthermore, the time of introgression of the D allele into humans -- about 37,000 years ago -- is when humans and Neanderthals coexisted in many parts of the world.

Lahn said the group's data suggest that the interbreeding was unlikely to be a thorough genetic mixing, but rather a rare - and perhaps even a single -- event that introduced the ancestral D allele previously present in this other Homo species into the human line.

“By no means do these findings constitute definitive proof that a Neanderthal was the source of the original copy of the D allele,” said Lahn. “However, our evidence shows that it is one of the best candidates. The timeline - including the introgression of the allele into humans 37,000 years ago and its origin in a lineage that separated with the human line 1.1 million years ago -- agrees with the contact between, and the evolutionary history of, Neanderthals and humans.

“And a third line of evidence, albeit weaker, is that the D alleles are much more prevalent in Eurasia and lower in sub-Saharan Africa, which is consistent with an origin in the former area. And we know that Neanderthals evolved outside of Africa,” said Lahn.

Lahn also said that although the disruption of the microcephalin gene in humans leads to smaller brains, the role of the D alleles in brain evolution remains unknown. “The D alleles may not even change brain size; they may only make the brain a bit more efficient if it indeed affects brain function,” he said. “For example, someone inheriting the D allele may have only a slightly more efficient brain on average. While that enhancement might confer only a subtle evolutionary advantage on that person, when that effect is propagated over a thousand generations of natural selection, the result will be to drive the D alleles to a very high prevalence.”

Lahn and his colleagues believe that other genes might well show similar telltale signs of an origin in archaic Homo lineages such as Neanderthals. They are currently using their analytical tool to search for evidence of that origin for other genes in the human genome.

Such findings may have broader implications for understanding human evolution than just revealing the possibility of human-Neanderthal interbreeding, he said. “In addition to being perhaps the most robust genetic evidence for introgression of genes from archaic Homo species into humans, I think this finding demonstrates that the evolution of our species has been profoundly impacted by gene flow from our relative species,” said Lahn.

“Finding evidence of mixing is not all that surprising. But our study demonstrates the possibility that interbreeding contributed advantageous variants into the human gene pool that subsequently spread. This implies that the evolution of human biology has been affected by the contribution of advantageous genetic variants from archaic relatives that we have replaced or even killed off,” he said.

Until now, said Lahn, the scientific debate over genetic exchange between humans and other Homo species has led to two prominent competing theories. One holds that anatomically modern humans replaced archaic species, with no interbreeding. And the other states that extensive interbreeding did take place and that modern humans evolved from that interbreeding in many regions of the world.

Genetic and fossil evidence for the latter “multiregional” theory has been inconclusive, said Lahn, so that theory has been largely discredited. However, he said, the newer evidence of gene exchange -- as well as other genetic evidence that might follow -- could give rise to a more moderate version holding that some genetic exchange did take place. Furthermore, it will become increasingly appreciated that such genetic exchange might have made our species much more fit.
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http://www.hhmi.org/news/could-inte...nd-neanderthals-have-led-enhanced-human-brain
 
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