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400,000 Year Old Human DNA Found

The New York Times reports on a new find that raises interesting questions about human evolution:

Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries.

In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years.

The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found.

The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery.

“Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study.

Hints at new hidden complexities in the human story came from a 400,000-year-old femur found in a cave in Spain called Sima de los Huesos (“the pit of bones” in Spanish). The scientific team used new methods to extract the ancient DNA from the fossil.

“This would not have been possible even a year ago,” said Juan Luis Arsuaga, a paleoanthropologist at Universidad Complutense de Madrid and a co-author of the paper.

Finding such ancient human DNA was a major advance, said David Reich, a geneticist at Harvard Medical School who was not involved in the research. “That’s an amazing, game-changing thing,” he said.

Since the 1970s, Spanish scientists have brought out a wealth of fossils from the cave dating back hundreds of thousands of years. “The place is very special,” said Dr. Arsuaga, who has found 28 nearly complete skeletons of humans during three decades of excavations.

Based on the anatomy of the fossils, Dr. Arsuaga has argued that they belonged to ancestors of Neanderthals, which lived in western Asia and Europe from about 200,000 to 30,000 years ago.

When Dr. Meyer and his colleagues drilled into the femur, they found ancient human DNA inside, just as they had hoped.

“Our expectation was that it would be a very early Neanderthal,” Dr. Meyer said.

But the DNA did not match that of Neanderthals. Dr. Meyer then compared it to the DNA of the Denisovans, the ancient human lineage that he and his colleagues had discovered in Siberia in 2010. He was shocked to find that it was similar.

“Everybody had a hard time believing it at first,” Dr. Meyer said. “So we generated more and more data to nail it down.”

The extra research confirmed that the DNA belonged on the Denisovan branch of the human family tree.

The new finding is hard to reconcile with the picture of human evolution that has been emerging in recent years based on fossils and ancient DNA. Denisovans were believed to be limited to East Asia, and they were not thought to look so Neanderthal-like.

Based on previously discovered ancient DNA and fossil evidence, scientists generally agreed that humans’ direct ancestors shared a common ancestor with Neanderthals and Denisovans that lived about half a million years ago in Africa.

Their shared ancestors split off from humans’ lineage and left Africa, then split further into the Denisovans and Neanderthals about 300,000 years ago. The evidence suggested that Neanderthals headed west, toward Europe, and that the Denisovans moved east.

Humans’ ancestors, meanwhile, stayed in Africa, giving rise to Homo sapiens about 200,000 years ago. Humans then expanded from Africa into Asia and Europe about 60,000 years ago. They then interbred not only with Neanderthals, but with Denisovans, too. Later, both the Denisovans and Neanderthals became extinct.

“Now we have to rethink the whole story,” Dr. Arsuaga said.

The most obvious answer, of course, would seem to be the humanity’s ancestors left Africa far earlier than we have previously though, which itself raises question about just how far modern humans spread before finally becoming dominant over their Neanderthal cousins that were located principally in Europe.

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About Doug Mataconis
Doug holds a B.A. in Political Science from Rutgers University and J.D. from George Mason University School of Law. He joined the staff of OTB in May, 2010 and also writes at Below The Beltway. Follow Doug on Twitter | Facebook

Comments

  1. stonetools says:

    The story of human ancestry really looks like a complex web, rather than the “March of Progress” enshrined in the famous illustration.My bet as to the most likely explanation is found in the article:

    One alternative explanation is that the humans of Sima de los Huesos were not true Neanderthals, but belonged to the ancestors of both Denisovans and Neanderthals.

    Another possibility: That lineage survives today in the current Texas Republican Party.

    Like or Dislike: Thumb up 8 Thumb down 3

  2. Neil Hudelson says:

    I find it hard to believe they found a human bone from 394,000 years before the universe was formed.

    Highly-rated. Helpful or Unhelpful: Thumb up 27 Thumb down 1

  3. rudderpedals says:

    Pat Buchanan went to Holocene Park and finally met a true paleocon. Talk about your troglodyte.

    That Spanish cave is amazing.

    Like or Dislike: Thumb up 0 Thumb down 0

  4. PJ says:

    And they say that god can’t joke.

    Like or Dislike: Thumb up 1 Thumb down 0

  5. John says:

    The theory of evolution is factually unsubstantiated. The majority of its given evidences have long been proven false by secular scientists, (transitional fossils, carbon dating, vestigial organs, old earth ect…) or are inapplicable to the theory. Remaining evidences are based on assumptions and wishful thinking. Not science.
    http://www.answersingenesis.org/get-answers#/topic/evolution

    http://www.answersingenesis.org / http://www.icr.org / http://www.evolutionvsgod.com

    Poorly-rated. Helpful or Unhelpful: Thumb up 0 Thumb down 26

  6. george says:

    @John:

    The theory of evolution is factually unsubstantiated. The majority of its given evidences have long been proven false by secular scientists, (transitional fossils, carbon dating, vestigial organs, old earth ect…) or are inapplicable to the theory. Remaining evidences are based on assumptions and wishful thinking. Not science.

    Sure, just like no one’s actually seen an electron or proton, and there are tons of secular scientists (Google if you doubt) who’ve disproven quantum mechanics to their own sastisfaction. Therefore atomic physics is unsubstantiated.

    Like or Dislike: Thumb up 5 Thumb down 0

  7. C. Clavin says:

    @John:
    From one of John’s links:

    The observed evidence in the present concerning genetic changes supports the Genesis text that God created all the animal kinds and human kind during the Creation Week.

    Creation Week? Is that on the Discovery Channel? Like Shark Week?
    Holy ignorance, Batmanneanderthal.

    Like or Dislike: Thumb up 5 Thumb down 0

  8. john personna says:

    @John:

    See sophistry.

    BTW, this from your first link is overtly, factually, wrong:

    Mutations and genetic drift are often cited as the source of heritable traits from one generation to the next. While mutations do cause changes in the genome and genetic drift changes the frequency of those traits, neither process is capable of changing one kind of animal into another. More often, mutations have either no noticeable impact or cause degeneration.

    One example I find interesting (having been an aquarist in my youth):

    Evidence for rapid speciation in African cichlid fishes

    Like or Dislike: Thumb up 1 Thumb down 0

  9. Matt says:

    @george: Except you can see evolution in action..

    http://phys.org/news202970888.html

    for example.

    Like or Dislike: Thumb up 1 Thumb down 0

  10. george says:

    @Matt:

    As far as that goes, you can see it in action with protozoa, bacteria, viruses – but I figure anyone who thinks that evolution has been factually unsubstantiated has long ago decided that traits aren’t passed via DNA and isn’t going to be convinced to the contrary by anything I can say. They’ve obviously come up with some alternative mechanism for passing traits between generations that doesn’t involve evolution (ie passing some sort of information between parents and offspring and then having survival/reproduction determine if that information gets passed on to further generations), though John doesn’t give a link to what his is.

    I was more amused by the reference to “secular scientists”, because you can find secular scientists who will back any theory you want backed (do a Google on all the physicists who’ve got web pages showing how Einstein and everyone but them has relativity all wrong). You can even find all sorts of secular scientists who’ve designed perpetual motion machines (again Google for a good laugh), who they’re sure are only ignored because the established scientific community (and maybe the oil companies) is in a conspiracy against them.

    Like or Dislike: Thumb up 2 Thumb down 0

  11. James in Silverdale, WA says:

    @John: “Remaining evidences are based on assumptions and wishful thinking.”

    This seems to be projection on your part. Why is evolution so distasteful to you?

    Like or Dislike: Thumb up 1 Thumb down 0

  12. john personna says:

    @James in Silverdale, WA:

    I have a guess. Everyone I know who is strongly anti-evolution lives in a network (family, friends, church) that holds strict creationism as a membership token. One can’t change one’s mind on the “theory” without breaking from the network. And so they are quick to name the standard answers to any of the related sciences. The answers are shields. It is sadly a carefully schooled sophistry,

    In contrast, the science of evolution has a long history of battle and change. Broadly evolution has held, but mechanisms and types and rates and whatever change constantly. To what degree did evolution shape our psychology? Hold on to your hat, that’s a big fight, ongoing.

    Like or Dislike: Thumb up 3 Thumb down 0

  13. Ron Beasley says:

    There was an article a coupe of weeks ago that said Europeans had about 2% neanderthal genome sequences and that Papua New Guineans and Australian Aboriginals share about 4% of their DNA with the Denisovans. What that means is that when the decedents of modern humans left Africa 60,000 years ago there was some interbreeding when they reached Europe and Oceana. Probably not a lot but some.

    Like or Dislike: Thumb up 2 Thumb down 0

  14. DrDaveT says:

    It is possible, for example, that there are many extinct human populations that scientists have yet to discover.

    Ding ding ding! Correct!

    The notion that hominids (or whatever the current preferred term is) were uniquely linear in their evolution, among all species, was always silly.

    (Though not as silly as John up above there. The real question is whether he’s been lurking here all along, or has a webcrawler that spots any and all mentions of evolution so that he can then send in his precision munition…)

    Like or Dislike: Thumb up 1 Thumb down 0

  15. ernieyeball says:

    @John: Not science.

    Of course Genesis is not science either. It is a fairy tale.

    Like or Dislike: Thumb up 1 Thumb down 0

  16. editor-b says:

    But, is there evolution if there is no time? How will evolutionary biology meet new physical paradigms about time, space and so on? Will new conceptual changes deny evolution? Or on the contrary, will it become a more extraordinary process, full of astonishing implications? Will human being nature become different as science progresses? Can knowledge change human beings, can it change you? Along these lines, a serious-funny b-book recommendation, a preview in http://goo.gl/rfVqw6 Just another leisure-suggestion

    Like or Dislike: Thumb up 0 Thumb down 5

  17. editor-b says:

    However, is there evolution if there is no time? How will evolutionary biology meet new physical paradigms about time, space and so on? Will new conceptual changes deny evolution? Or on the contrary, will it become a more extraordinary process, full of astonishing implications? Will human being nature become different as science progresses? Can knowledge change human beings, can it change you? Along these lines, a serious-funny b-book recommendation, a preview in http://goo.gl/rfVqw6 Just another leisure-suggestion

    Like or Dislike: Thumb up 0 Thumb down 3