Posted on 12/19/2013 12:22:35 PM PST by 2ndDivisionVet
A high-quality genome sequence obtained from a female Neanderthal toe bone reveals that the individual’s parents were close relatives and that such inbreeding was prevalent among her recent ancestors, according to a paper published today (December 18) in Nature. But the sequence also reveals that interbreeding occurred between Neanderthals and other hominin groups, including early modern humans.
“Did humans evolve like a constantly branching tree? A lot of people think so,” said Milford Wolpoff, a professor of anthropology at the University of Michigan, who was not involved in the study. “But there’s also been this thread of thought, by some people like me, that humans evolved more like a network, where there are different populations and they split and sometimes they come back together and they mate.” The new toe bone sequence data, he said, is “really important because it’s giving us good evidence that there’s been constant interbreeding between different human groups all through prehistory.”
The toe bone was found in a cave in Denisova, Siberia, where the conditions for DNA preservation are near-perfect. “The cave year-round has an average temperature of zero degrees Celsius and that’s probably helping to contribute to the preservation,” explained John Hawks, a professor of anthropology at the University of Wisconsin, who also did not participate in the study.
Indeed, the toe bone and its DNA were so well preserved that it was possible to obtain sequence data that “is on the same level, as far as quality goes, as many other modern human genomes,” said Kay Prüfer, an evolutionary geneticist from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who led the study. “For every position in the genome we have on average 50 fragments covering it, which is amazing,” he said. Just how amazing? Previously sequenced Neanderthal genomes have average coverages of 0.5 to 1.3.
Also amazing, was the fact that the toe bone was Neanderthal at all. Previous bone and tooth samples found in the cave had yielded high-quality DNA sequences identified as belonging to a new and different group of hominins called the Denisovans, who were named after the location. “We were expecting that it [the toe] would be another Denisovan,” said Prüfer, “but, to our surprise, it wasn’t.”
Another surprise followed. The high degree of coverage allowed the team to observe subtle sequence differences that were present in the maternal and paternal copies of the chromosomes. But “what we actually saw was that there are long stretches where the two copies of the chromosomes were actually very, very similar,” said Prüfer, “and that essentially means that the two parents must have been closely related.” From the team’s calculations, the parents were likely half siblings, an uncle and niece, or similar. And further sequence analysis indicated that inbreeding had been typical among the individual’s recent ancestors. In fact, the level of variation “was among the lowest observed for any organism,” Prüfer said.
Despite the high degree of inbreeding that took place in the family of this particular Neanderthal—named the Altai Neanderthal—there was also evidence that Neanderthals in general interbred with other hominin groups. The team compared the genomes of the Altai Neanderthal, a Denisovan, a number of modern humans, and Neanderthals from Croatia and the Caucasus mountains, and confirmed earlier indications that modern humans contain both Neanderthal and Denisovan DNA.
They also showed that Denisovans contained both Neanderthal DNA sequences—most similar to that from the Altai Neanderthal—and sequences absent from Neanderthals and modern humans, which thus appear to have come from an unknown archaic hominin group.
“The general picture is that we have lots of different admixtures. So we see that any type of human group . . . seems to have some exchange of [genetic] material with another group,” Prüfer said.
Besides revealing the complexities of ancient hominin mating habits, the high-quality Neanderthal and Denisovan genomes should also help scientists better understand modern humans, said Prüfer. “We can now ask: What are the variants on the human lineage that are definitely new and that we all have and. . . that enabled us to do certain things that Neanderthals and Denisovans didn’t accomplish, including growing to now seven billion people, living all over the planet, and having airplanes to go from A to B? If there is some genetic basis to that, then it is hidden in these changes,” he said.
The good news, said Hawks, is that such genetic changes are few. “There is not that much that sets modern humans apart from these ancient people . . . and that’s a pretty cool message,” he said.
K. Prüfer et al., “The complete genome sequence of a Neanderthal from the Altai Mountains,” Nature, doi:10.1038/nature12886, 2013.
No, not for over 10 year. BUT THERE HAS BEEN!
Do you think we're unaware of this stuff? There was "global warming" at the time of the dustbowl in the Dirty Thirties.
the Sun’s solar cycles are really slowing down, much smaller.
all indications point to something like another maunder minimum (mini ice age).it started this year with the biggest 1 year drop in temps in a long time. global warming is a hoax.
see you here in a few years when it’s even colder. will you still believe in global warming? I’ll be having fun destroying liberals/democrats all over the internet as i am this year with all the cold weather headlines .
“Weakest Solar Cycle In Almost 200 Years”
The sun is acting bizarrely and scientists have no idea why. Solar activity is in gradual decline, a change from the norm which in the past triggered a 300-year-long mini ice age. We are supposed to be at a peak of activity, at solar maximum. The current situation, however, is outside the norm and the number of sunspots seems in steady decline. The sun was undergoing “bizarre behaviour” said Dr Craig DeForest of the society. “It is the smallest solar maximum we have seen in 100 years,” said Dr David Hathaway of Nasa. –Dick Ahlstrom, The Irish Times, 12 July 2013
Well, there used to be hundreds of feet of ice right here.
What happened to it and why?
Nikolai Sergeyevich Valuev (Russian: Николай Сергеевич Валуев Russian pronunciation: [nʲɪkɐˈlaj sʲɪrˈɡʲejɪvʲɪtɕ vɐˈlʊjɪf]; born 21 August 1973) is a retired Russian professional boxer and former two-time WBA heavyweight champion turned politician.
Present day and/or anthropogenic caused global warming is a hoax.
global warming is a hoax
it’s not getting warmer, although you do your best to help the evil liberal news media enslave us
hash tag global cooling
#solarcycle25
Please put your reading comprehension goggles on and reread my post. TY.
That’s because Neanderthals and Denisovans aren’t modern humans. Pretty simple.
Not sure I understand your point.
My comment was directed at the politically correct ideal that ALL modern humans can be traced back in a direct line to ancestors in sub-Saharan Africa.
Thus, according to that ideal, any form of racial prejudice or racial conceit is evil and ignorant because we all have the same ancestors.
But, if some of us uniquely carry DNA from other human species, then that ideal goes right out the window.
In a general sense I think I understand what you are saying - that the southern Africans are still my “relatives.”
I agree, but I’m also a DNA “relative” of 3 billion year old bacteria, but I’m not sure that fact helps us in the present discussion.
There is nothing PC about it.
Neanderthals also originated in Africa. While there is more to be learned and discovered than what we actually know right now, there is no evidence of a humanoid species of non-African origin. Applying any modern day ‘racial’ component to evolution would be pc nonsense. DNA doesn’t care about political correctness.
My point:
There are no native born Homo Sapiens Sapiens in southern Africa who carry Neanderthal or Denisovan DNA.
Outside of southern Africa, there are definitely Homo Sapiens Sapiens who have Neanderthal and Denisovan DNA.
Why are those two distinct groups of Homo Sapiens Sapiens considered to be part of the same Hominim species?
They all branch from a common ancestor that originated in Africa and migrated out from there. Homo species migrated out of Africa LONG before modern humans, including the Neanderthal.
Our branch is relatively new and survived, the others died out. When inter-breeding was possible it apparently happened because traces of the other hominid species DNA can be found, but the species it came from is no longer around.
Do you understand that Neanderthal, Denisovan, and Sapiens are three distinct Hominim species?
Just so I'm clear, you state that Homo Sapiens Sapiens WITH Neanderthal and Denisovan DNA should be classified as the same species as Homo Sapiens Sapiens with NO Neanderthal or Denisovan DNA.
Do I understand you correctly?
“Do you understand that Neanderthal, Denisovan, and Sapiens are three distinct Hominim species?”
Yes, and it should be obvious from my post, frankly.
“Just so I’m clear, you state that Homo Sapiens Sapiens WITH Neanderthal and Denisovan DNA should be classified as the same species as Homo Sapiens Sapiens with NO Neanderthal or Denisovan DNA.”
The genetic drift in some populations of current humans from previous, extinct homo species is small and doesn’t change the species classification now, it is a remnant of our past, showing that inter-breeding was possible.
So to answer directly, yes, same species. People with small remnants of DNA from other homo species still belong to our species. You know we share over 98% of our DNA with chimps, still a different species.
That last sentence didn’t follow the logic of my point quite like I intended. Not proud of it.
there’s white stuff , ice and snow , all over the USA . is that white stuff global warming? lol
hash tag global warming is a hoax
there is
#global cooling now
that thing in the middle of the solar system that is a milion times larger than the Earth says so, cooling , ok? got it?
Your response suggests you've read the talking points but have no idea what you are actually talking about or the science behind it. You are essentially the same as the average global warming believer and make a perfect example for liberals to point to as a "denier". Clueless but convinced.
Until you show some sign that you have actually read my post I will assume you are a dunce or a jester.
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