Early Humans Bred With Neanderthals, Denisovans

Started by stromboli, March 18, 2016, 12:56:21 PM

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stromboli

http://www.nytimes.com/2016/03/22/science/neanderthals-interbred-with-humans-denisovans.html?_r=0

QuoteThe ancestors of modern humans interbred with Neanderthals and another extinct line of humans known as the Denisovans at least four times in the course of prehistory, according to an analysis of global genomes published on Thursday in the journal Science.

The interbreeding may have given modern humans genes that bolstered immunity to pathogens, the authors concluded.

“This is yet another genetic nail in the coffin of our over-simplistic models of human evolution,” said Carles Lalueza-Fox, a research scientist at the Institute of Evolutionary Biology in Barcelona who was not involved in the study.

The new study expands on a series of findings in recent years showing that the ancestors of modern humans once shared the planet with a surprising number of near relatives â€" lineages like the Neanderthals and Denisovans that became extinct tens of thousands of years ago.

Before disappearing, however, they interbred with our forebears on at least several occasions, and today we carry DNA from these encounters.

The first clues to ancient interbreeding surfaced in 2010, when scientists discovered that some modern humans â€" mostly Europeans â€" carry DNA that matches material recovered from Neanderthal fossils.

Later studies showed that the forebears of modern humans first encountered Neanderthals after expanding out of Africa more than 50,000 years ago.

But the Neanderthals were not the only extinct humans that our own ancestors found. A finger bone discovered in a Siberian cave, called Denisova, yielded DNA from yet another group of humans.

Research later indicated that all three groups â€" modern humans, Neanderthals and Denisovans â€" shared a common ancestor who lived roughly 600,000 years ago. And, perhaps no surprise, some ancestors of modern humans also interbred with Denisovans.
Some of their DNA has survived in people in Melanesia, a region of the Pacific that includes New Guinea and the islands around it.

Those initial discoveries left major questions unanswered, such as how often our ancestors interbred with Neanderthals and Denisovans. Scientists have developed new ways to study the DNA of living people to tackle these mysteries.

Joshua M. Akey, a geneticist at the University of Washington, and his colleagues analyzed a database of 1,488 genomes from people around the world. The scientists added 35 genomes from people in New Britain and other Melanesian islands in an effort to learn more about Denisovans in particular.

The researchers found that all the non-Africans in their study had Neanderthal DNA, while the Africans had very little or none. That finding supported previous studies.

But when Dr. Akey and his colleagues compared DNA from modern Europeans, East Asians and Melanesians, they found that each population carried its own distinctive mix of Neanderthal genes.

The best explanation for these patterns, the scientists concluded, was that the ancestors of modern humans acquired Neanderthal DNA on three occasions.

The first encounter happened when the common ancestor of all non-Africans interbred with Neanderthals.

The second occurred among the ancestors of East Asians and Europeans, after the ancestors of Melanesians split off. Later, the ancestors of East Asians â€" but not Europeans â€" interbred a third time with Neanderthals.

Earlier studies had hinted at the possibility that the forebears of modern humans had multiple encounters with Neanderthals, but until now hard data was lacking.

“A lot of people have been arguing for that, but now they’re really providing the evidence for it,” said Rasmus Nielsen, a geneticist at the University of California, Berkeley, who was not involved in the new study.

The Melanesians took a different course. After a single interbreeding with Neanderthals, Dr. Akey found, their ancestors went on to interbreed just once with Denisovans, as well.

Where that encounter could have taken place remains an enigma. The only place Denisovan remains have been found is Siberia, a long way from New Guinea.

It is possible that Denisovans ranged down to Southeast Asia, Dr. Akey said, crossing paths with modern humans who would later settle in Melanesia.

Dr. Akey and his colleagues also identified some regions of Neanderthal and Denisovan DNA that became more common in modern humans as the generations passed, suggesting that they provided some kind of a survival advantage.

Many of the regions contain immune system genes, Dr. Akey noted.

“As modern humans are spreading out across the world, they’re encountering pathogens they haven’t experienced before,” he said. Neanderthals and Denisovans may have had genes that were adapted to fight those enemies.

“Maybe they really helped us survive and thrive in these new environments,” he said.

Dr. Akey and his colleagues found that Neanderthal and Denisovan DNA was glaringly absent from four regions of the modern human genome.

That absence may signal that these stretches of the genome are instrumental in making modern humans unique. Intriguingly, one of those regions includes a gene called FOXP2, which is involved in speech.

Scientists suspect that Neanderthals and Denisovans were not the only extinct races our ancestors interbred with.

PingHsun Hsieh, a biologist at the University of Arizona, and his colleagues reported last month that the genomes of African pygmies contain pieces of DNA that came from an unknown source within the last 30,000 years.

Dr. Akey and his colleagues are now following up with an analysis of African populations. “This potentially allows us to find new twigs on the human family tree,” he said.

And may your red haired cross eyed cousin live long and prosper.  :wink:

aitm

I humped a Denise several dozen times, so I agree with this message.....
A humans desire to live is exceeded only by their willingness to die for another. Even god cannot equal this magnificent sacrifice. No god has the right to judge them.-first tenant of the Panotheust

stromboli

Quote from: aitm on March 18, 2016, 02:03:13 PM
I humped a Denise several dozen times, so I agree with this message.....

If she was a redhead you got the whole package.  :biggrin:

Baruch

Whether one interbreeds (and if one can, then it isn't a separate species) or if one has common ancestry (which is guaranteed) is hard to prove, particularly if you don't have video of Cro-Magnons making out with Neanderthals.  But in science today, evidence isn't that important.

Why are European derived folks so happy about this percentage of Neanderthal in their genome?  Because they want to not be ultimately from Africa, they want to be zero percent African, because racism.  But they aren't getting the irony ... Neanderthals used to be a joke, now they are an esteemed ancestry ;-)  The greater percentage of Neanderthal among Europeans might explain why Europeans have so many undesirable traits.
Ha’át’íísh baa naniná?
Azee’ Å,a’ish nanídį́į́h?
Táadoo ánít’iní.
What are you doing?
Are you taking any medications?
Don't do that.

AllRight

Neanderthals still exist...I work with a few of them!

Gawdzilla Sama

Lee Burger goes with the "braided stream" of human development. He says we've interbred and separated lines many times. When you have to have a Ph.D. to differentiate between "your" people and "those" people it's not hard to picture people interbreeding. It would strengthen the overall breed.
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

josephpalazzo

Quote from: stromboli on March 18, 2016, 12:56:21 PM
Quotehttp://www.nytimes.com/2016/03/22/science/neanderthals-interbred-with-humans-denisovans.html?_r=0
The ancestors of modern humans interbred with Neanderthals and another extinct line of humans known as the Denisovans at least four times in the course of prehistory, according to an analysis of global genomes published on Thursday in the journal Science.

The interbreeding may have given modern humans genes that bolstered immunity to pathogens, the authors concluded.

“This is yet another genetic nail in the coffin of our over-simplistic models of human evolution,” said Carles Lalueza-Fox, a research scientist at the Institute of Evolutionary Biology in Barcelona who was not involved in the study.

The new study expands on a series of findings in recent years showing that the ancestors of modern humans once shared the planet with a surprising number of near relatives â€" lineages like the Neanderthals and Denisovans that became extinct tens of thousands of years ago.

Before disappearing, however, they interbred with our forebears on at least several occasions, and today we carry DNA from these encounters.

The first clues to ancient interbreeding surfaced in 2010, when scientists discovered that some modern humans â€" mostly Europeans â€" carry DNA that matches material recovered from Neanderthal fossils.

Later studies showed that the forebears of modern humans first encountered Neanderthals after expanding out of Africa more than 50,000 years ago.

But the Neanderthals were not the only extinct humans that our own ancestors found. A finger bone discovered in a Siberian cave, called Denisova, yielded DNA from yet another group of humans.

Research later indicated that all three groups â€" modern humans, Neanderthals and Denisovans â€" shared a common ancestor who lived roughly 600,000 years ago. And, perhaps no surprise, some ancestors of modern humans also interbred with Denisovans.
Some of their DNA has survived in people in Melanesia, a region of the Pacific that includes New Guinea and the islands around it.

Those initial discoveries left major questions unanswered, such as how often our ancestors interbred with Neanderthals and Denisovans. Scientists have developed new ways to study the DNA of living people to tackle these mysteries.

Joshua M. Akey, a geneticist at the University of Washington, and his colleagues analyzed a database of 1,488 genomes from people around the world. The scientists added 35 genomes from people in New Britain and other Melanesian islands in an effort to learn more about Denisovans in particular.

The researchers found that all the non-Africans in their study had Neanderthal DNA, while the Africans had very little or none. That finding supported previous studies.

But when Dr. Akey and his colleagues compared DNA from modern Europeans, East Asians and Melanesians, they found that each population carried its own distinctive mix of Neanderthal genes.

The best explanation for these patterns, the scientists concluded, was that the ancestors of modern humans acquired Neanderthal DNA on three occasions.

The first encounter happened when the common ancestor of all non-Africans interbred with Neanderthals.

The second occurred among the ancestors of East Asians and Europeans, after the ancestors of Melanesians split off. Later, the ancestors of East Asians â€" but not Europeans â€" interbred a third time with Neanderthals.

Earlier studies had hinted at the possibility that the forebears of modern humans had multiple encounters with Neanderthals, but until now hard data was lacking.

“A lot of people have been arguing for that, but now they’re really providing the evidence for it,” said Rasmus Nielsen, a geneticist at the University of California, Berkeley, who was not involved in the new study.

The Melanesians took a different course. After a single interbreeding with Neanderthals, Dr. Akey found, their ancestors went on to interbreed just once with Denisovans, as well.

Where that encounter could have taken place remains an enigma. The only place Denisovan remains have been found is Siberia, a long way from New Guinea.

It is possible that Denisovans ranged down to Southeast Asia, Dr. Akey said, crossing paths with modern humans who would later settle in Melanesia.

Dr. Akey and his colleagues also identified some regions of Neanderthal and Denisovan DNA that became more common in modern humans as the generations passed, suggesting that they provided some kind of a survival advantage.

Many of the regions contain immune system genes, Dr. Akey noted.

“As modern humans are spreading out across the world, they’re encountering pathogens they haven’t experienced before,” he said. Neanderthals and Denisovans may have had genes that were adapted to fight those enemies.

“Maybe they really helped us survive and thrive in these new environments,” he said.

Dr. Akey and his colleagues found that Neanderthal and Denisovan DNA was glaringly absent from four regions of the modern human genome.

That absence may signal that these stretches of the genome are instrumental in making modern humans unique. Intriguingly, one of those regions includes a gene called FOXP2, which is involved in speech.

Scientists suspect that Neanderthals and Denisovans were not the only extinct races our ancestors interbred with.

PingHsun Hsieh, a biologist at the University of Arizona, and his colleagues reported last month that the genomes of African pygmies contain pieces of DNA that came from an unknown source within the last 30,000 years.

Dr. Akey and his colleagues are now following up with an analysis of African populations. “This potentially allows us to find new twigs on the human family tree,” he said.
And may your red haired cross eyed cousin live long and prosper.


So many words just to say that humans have been fucking since day ONE. :thanx:

SGOS

This idea has been around for awhile.  I remember first hearing about it a few years ago, and it became popular.  Then for some reason, it seemed to fall out of favor.  Now it's headed back into the mainstream.  New ideas are seldom embraced by everyone all at once.  These things gain acceptance through verification, but not everyone embraces the verification.  Within the scientific community, scientists are the harshest of critics.  The fight back with facts and different findings.  Some might be partial to pet theories, but at the end of the debate, a consensus is formed, and that becomes the current state of our knowledge base, but even this can change.

The knowledge base of physical anthropology has changed since I took that course back in the 60s.  I don't think Lucy had been discovered when I took the class, although the australopithecines, were fairly well known.  It changes still today.  We haven't discovered enough of the fossil record to understand our past as well as we would like, partly because humans haven't been around long enough to become much of that fossil record, but we are sorting things out.  This Genome thing is just getting started, and who knows what other technologies will come along?

I believe we did mate with Neanderthals, simply because they were around when we were.  If some guy today will have sex with a blow up doll, you can bet some Cro-Magnon loser would have sex with a Neanderthal.  Apparently, they produced offspring too from what the DNA seems to tell us.  I wouldn't get too caught up in the definition of species too quickly.  Just because Neanderthals were put in a different taxonomic category doesn't make it the end all be all of breeding, and the lines between closely related species don't show up over night.  There's lots of interbreeding going on all the time while species diverge.  It could go on for millions of years, before the DNA changes enough to prevent viable offspring.

aitm

Quote from: josephpalazzo on March 19, 2016, 10:38:40 AM

So many words just to say that humans have been fucking since day ONE. :thanx:

more likely a little closer to raping one would imagine.
A humans desire to live is exceeded only by their willingness to die for another. Even god cannot equal this magnificent sacrifice. No god has the right to judge them.-first tenant of the Panotheust

Gawdzilla Sama

Quote from: aitm on March 19, 2016, 11:30:37 AM
more likely a little closer to raping one would imagine.
I would go with rough sex over rape. Women get horny too, or so I've heard. Foreplay advocates forget the first three plays. :)
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

stromboli

Quote from: Gawdzilla Sama on March 19, 2016, 02:50:32 PM
I would go with rough sex over rape. Women get horny too, or so I've heard. Foreplay advocates forget the first three plays. :)


Gawdzilla Sama

We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

stromboli

You are entirely welcome. I figure to use the gif for worthy comments. So far the only ones are yours.

drunkenshoe

"science is not about building a body of known 'facts'. ıt is a method for asking awkward questions and subjecting them to a reality-check, thus avoiding the human tendency to believe whatever makes us feel good." - tp

Jack89

23andme DNA results provide you with your estimated percentage of Neanderthal DNA, if you have any.  I'm 2.9% which puts me in the 83rd percentile group.  The average European has about 2.7% Neanderthal DNA. 

Probably just a novelty item for 23andme, but it's kind of fun to play with.