Wednesday, June 16, 2010

Answers in Genesis on the Neandertal Genome

I missed this a month back. AIG weighed in on the sequencing of the Neandertal Genome here. If you will recall, it was found by Svante Paabo and colleagues that Neandertals appear to have contributed at least 4% of their DNA to modern humans, thus strongly suggesting that the speciation event in sub-Saharan Africa that gave rise to modern humans was not total, with at least some interbreeding between the two groups. The article by Layman, reads thus:

The news doesn’t surprise young-earth creationists, who predicted overlap between modern human and Neanderthal genomes. Based on Scripture, creationists consider Neanderthals to have been fully human, descendants of Adam and Eve (through Noah), and therefore they would have lived in the same time and place as other humans. But factors related to both the dispersion at Babel and environmental pressures afterward resulted in people groups with different physical characteristics, including humans with “Neanderthal” characteristics.

Liberty University cell biologist (and creationist) David DeWitt called the research an “amazing feat” of science that supports creationist expectations. “Finding Neanderthal DNA in humans was not expected by evolutionists, but it was predicted from a creation standpoint because we have said all along that Neanderthals were fully human: descendants of Adam and Eve, just like us,” he told News to Note.

There is no explanation as to why this finding would "not be expected by evolutionists." There are quite a few models that would welcome this sort of explanation. It is only unexpected if you are unfamiliar with the data or the models. As for whether Neandertals were "fully human," there is a problem with that: Neandertals aren't fully human. That is the source of the controversy in the first place. Many anthropologists regard them as a separate species of human based on their distinctness from modern humans.

The Neandertals represented a distinct European and Near Eastern variant of what has become known as "archaic Homo sapiens." This is a grade of Homo sapiens that existed after Homo erectus/ergaster but before true Homo sapiens, which are decidedly different. As biological anthropologist Dave Frayer has pointed out, there is not a single person alive that has the full suite of Neandertal characteristics. For example, in the following diagram, it is clear that there are sharp differences between these two hominid forms.



Several things are immediately apparent in this comparison. The modern human individual has much reduced ridges over the eyes, a much more vaulted forehead, a smaller nose opening, a shorter, higher cranium, smaller teeth and more forward-placed cheek bones.

There are those that argue, however, that the earliest modern humans have traits that are holdovers from the preceding Neandertals. And for those of us that hold to this perspective, this finding was perfectly expected. The last Neandertals date to around 30 thousand years ago and this overlaps with the earliest modern humans, which date to between 34 and 37 thousand years. At the point of this overlap, the earliest moderns, which are likely migrants from the Near East, either mated with the Neandertals or replaced them. While there has been evidence from the crania of the earliest moderns that some degree of interpopulational mating has occurred, the DNA evidence has largely supported the replacement idea. Svante Paabo's evidence changes that.

Anthropologist Richard Klein has stated that he doesn't see how any modern human would have found a Neandertal attractive enough to mate with. What the findings from the Neandertal genome show us is that two very different groups of people met somewhere in Europe between 30 and 40 thousand years ago and that some of the moderns did find the Neandertals suitable as mates. But modern human the Neandertals certainly were not.

P.S. Why don't sites like AIG and the Discovery Institute allow comments by readers? It would have been nice to simply point this out on the AIG site.

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8 comments:

  1. Jim, As I commented before If Neanderthals interbred with Humans [and produced fertile offspring],wouldn't that make them the same species? If not, what category of species would they be? Are there other examples where such cross specie genomic transfer has occurred through interbreeding?

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  2. The model that is being floated by some is that of the "liger," a tiger-lion cross as well as the crosses between wolves and dogs (wogs?). I remember my advisor once upon a time suggesting what you are suggesting—how much interbreeding is too much to maintain the species barrier? The answer is no one really quite knows. Left to their own devices, however, dogs will mate with dogs and tigers will mate with tigers. Does the 4% represent a marriage of convenience?

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  3. Chris Massey5:10 PM

    Jim, I'm a bit confused by the picture in this article. I'm not used to seeing homo sapiens sapiens skulls with such large brow ridges. Surely modern humans don't have that pronounced brow ridge. (Feels face) I'm pretty sure I don't. Is that a Cro Magnon skull? The brow ridge appears to be almost as large as that of the Neanderthal. What exactly is that specimen? Thanks.

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  4. Chris, that skull is from the site of predmosti (pronounced "pshedmosti), in the Czech Republic that dates to around 27 ky BP. While it is true that the brow ridges are a bit thick, and the back of the head "buns" out a bit, in all other matters it is a modern human. Oh, and there are people out there today with brow ridges that thick. As I said in the post, though, there are no people alive that have the suite of characteristics present in the Neandertal skull on the left.

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  5. Chris Massey7:55 PM

    Dang, those poor folks won't be winning any beauty pageants. I wonder if the big brow ridge comes with a unibrow too. Thanks for the explanation.

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  6. "Anthropologist Richard Klein has stated that he doesn't see how any modern human would have found a Neandertal attractive enough to mate with."

    I thought it is clear the some humans happily mate with anything that moves. (Chimps also http://www.youtube.com/watch?v=qVE60zwXx1k)

    The other thing is that one can not decide whether HN and HSS are different species or not purely on bone-structure. The differences are much smaller than between certain dog breeds. Now it is proven that they in fact were not completely different species. And someone might argue that even Homo Erectus was not entirely different.

    With other species it thought that 400kY - 1 MY needed to complete speciation.

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  7. "P.S. Why don't sites like AIG and the Discovery Institute allow comments by readers? It would have been nice to simply point this out on the AIG site."

    Oh, feel welcome to comment on my Creationist blog.

    Creationist as in YEC.

    Here is the latest, joining two series on carbon dating, one theoretic, ending here with "advantages" which summarise aplications (I would not call them liabilities, but what would you call them - corroborating points?), and on the other hand a series with one of these applications concluding in this post.

    Links to previous of both series are given in top.

    Creation vs. Evolution : Advantages of a Shorter Carbon 14 Chronology / Letter A of ex oriente - IV - Conclusion
    http://creavsevolu.blogspot.fr/2016/11/advantages-of-shorter-carbon-14.html


    Most of the second series is on another blog, feel free to comment there too.

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  8. (Btw, on my blogs you don't have to wait until I approve your comments, in certain cases I will disapprove spam or profanity, but I don't worry about you).

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