One and Many

From Dennis Venema, at BioLogos:

It is reasonably well known among evangelical Christians that all living humans trace their mitochondrial DNA back to a single woman (a so-called “mitochondrial Eve”) and that all living males similarly trace their Y-chromosome DNA back to a single male (a so-called “Y-chromosome Adam”). These individuals are commonly assumed by evangelicals to be the Biblical Adam and Eve, the first humans alive and the progenitors of the entire human race. While most young-earth and old-earth creationist organizations make this claim, perhaps one of the best-known organizations to do so is the old-earth creationist / anti-evolution organization Reasons to Believe, who have produced numerous articles, podcasts, and even entire books on the subject.

In contrast to this common evangelical understanding, the scientific picture is rather different. Mitochondrial Eve, though the most recent common matrilineal ancestor of all humans, was but one of a large population living about 180,000 years ago. So too for Y-chromosome Adam: he was also a member of a large population, and he lived about 50,000 years ago. As has been discussed several times here at BioLogos, there are multiple lines of evidence that indicate the human population has never been below around 10,000 members at any time in its history: we branched off as a large population to form our own species.

When presented with the evidence for human population sizes over our evolutionary history, a common point of confusion for evangelicals is how this evidence fits with Mitochondrial Eve. How can we all come from one woman (and one man) but also come from a large population of 10,000 individuals? Aren’t these two observations in conflict?

The answer is no, these lines of evidence fit together. Humans do come from a large population, and all present-day humans do inherit mitochondrial and Y-chromosome DNA from specific individuals in the past. The reason for the apparent discrepancy lies in how mitochondrial and Y-chromosome DNA are inherited, as we shall see below.

About Scot McKnight

Scot McKnight is a recognized authority on the New Testament, early Christianity, and the historical Jesus. McKnight, author of more than forty books, is the Professor of New Testament at Northern Seminary in Lombard, IL.

  • http://www.huntingforwonder.com Daren Redekopp

    This is fascinating stuff. Thanks for posting!

  • Klasie Kraalogies

    The OEC / YEC crowd might want to read upon genetic drift, for instance.

  • AHH

    Yes, whichever scientist(s) cleverly inserted “Adam” and “Eve” when labeling this scientific concept ended up giving superficial cover to a lot of misinformed apologetics.

  • Tim

    Dennis is incorrect with respect to the organization Reasons to Believe, which does acknowledge the discrepancy in dating between mitochondrial Eve and Y-chromosome Adam and, in fact, has their own explanation for this discrepancy.

  • http://biologos.org/blog/author/dennis-venema Dennis Venema

    Of course, the new interesting finding is that there exists an (until recently) unknown Y chromosome lineage in humans that goes back to over 300,000 years ago. So, now our “genetic Adam” (for the Y chromosome) isn’t even within our species (Homo sapiens is about 200,000 years old, give or take). The Y chromosome ancestor for the vast majority of modern humans is still the one at ~50,000 years ago, though.

  • Klasie Kraalogies

    Dennis – that is interesting! Any links you could share?

  • http://laughingsquid.com/geneticists-discover-y-chromosome-that-predates-mankind/ Dennis Venema

    It was all over the news the other day – here’s one link (click on my name for it – don’t know how to embed links here).

  • https://www.cell.com/AJHG/retrieve/pii/S0002929713000736 Dennis Venema

    … and here’s the actual research paper (again, click my name for the link).

  • Klasie Kraalogies

    Thanks Dennis! It would appear that it is currently a very exciting time in the field of genetics. Regular, major discoveries. As a geologist, I’m quite jealous…

  • TJJ

    I think it is safe to say that a good many evangelicals, perhaps most, are woefully ignorant and/ or have mistaken notions of modern science and its current findings and the implications of those findings. I sat through a presentation at an EFCA national conference seminar on the topic of Genesis/creation. Frankly it was shocking how ignorant and out of touch it was. Sad, very sad. It is one rhibg to disagree with the scientifice conclusions regarding DNA evidence. But it is something else.to be wholly irgnorant or mistaken about what the evidence is.

  • AHH

    Tim @4:
    Do you have a link for your claim that Reasons to Believe actually recognizes this discrepancy and has some explanation for it?
    I find this article from 2010:
    http://www.reasons.org/articles/were-they-real-the-scientific-case-for-adam-and-eve
    where RTB gets things wrong in exactly the way Dennis Venema claims. If they have since recognized their mistakes, they should take down that erroneous 2010 article from their website or update it with correct information.

  • Dennis Venema

    I have yet to see RTB back away / correct their views on this, so if they have, I too would be interested in a link to back up the claim that they have.

    Also, having an “explanation” and having a scientifically valid explanation are not the same thing. RTB attempts the former, but is sorely lacking in the latter.

  • Tim

    I don’t have a link on hand nor do I have the desire to dig one up.

    However, I can assure everyone that I’ve heard Ross attribute the earlier dating of mitochondrial Eve relative to Y-chromosome Adam to the fact that after the flood all the surviving men had the same Y-chromosome (i.e., that of Noah) while the wives of Noah’s sons almost certainly exhibited variation in their mitochondrial DNA, hence the earlier date for mitochondrial Eve. Ross’s logic is sound aside from the fact he’s reading Gen 6-9 as a reliable historical account of a flood that affected all of humanity instead of a legendary account of a flood that affected a subset of humanity in ancient Mesopotamia.

  • Tim

    AHH,

    The article you linked to from the RTB website doesn’t assume that the earliest common male ancestor (i.e., Y-chromosome Adam) is the same as the earliest common female ancestor (i.e., mitochondrial Eve). Rather, it argues that humanity likely descended from a single primal couple on the basis that both our mitochondrial DNA and our Y-chromosome DNA trace back to a single ancestral sequence (i.e., those of mitochondrial Eve and Y-chromosome Adam).

  • Dennis Venema

    The point of interest here is that now we know the last common Y-chromosome ancestor of all living humans is older than “mitochondrial Eve.” That doesn’t fit with the RTB model, ad hoc though it might be.

  • Tim

    Dennis,

    The point of interest to me is that you misrepresented the folks at Reasons for purely rhetorical purposes. In my opinion, Ross et al. are well-intentioned in their efforts, though misguided, and certainly deserve better. In any case, the real trouble makers that are stunting evangelicalism’s theological growth in this area are the folks at AIG, few people around here will complain if you aim your rhetorical guns in that direction.

  • http://www.reenactingtheway.com Paul

    Please be careful not to use logic related to a universal flood when we have discovered now that the predominant use of the Hebrew “ge” (translated earth or land based on context and perspective) in Genesis refers to the land of Sumer, or the Mesopotamian basin inhabited by the Sumerians. The geographic and ancient literary context point to a regional flood of the Tigris-Euphrates basin. See my article providing the lexical evidence for that conclusion about “ge” as well as an extended argument for how the Babel story is a summarized retelling of the fall of the Sumerian empire around 2000 B.C. – http://www.etsjets.org/files/JETS-PDFs/50/50-4/JETS_50-4_693-714_Penley.pdf

  • Dennis Venema

    Tim, to the best of my knowledge I haven’t misrepresented RTB in any way, but merely critiqued their attempts to explain away data at odds with their model. If you can point out where you feel I have misrepresented them, please do so.

  • Tim

    Dennis,

    I already did at comment #4. The RTB model recognizes the old discrepancy between mitochondrial Eve and Y-chromosome Adam contra your blog post. For what it’s worth, I think it was an honest mistake, but there it is.

  • Dennis Venema

    Where in that blog post do I claim that RTB doesn’t attempt to account for the difference in dates? I don’t even mention it, because it isn’t relevant to the post. The only thing I say about RTB is that they claim it’s possible to interpret the data as coming from an ancestral pair, which is indeed what RTB claims – and this is where their model doesn’t fit the evidence. So, I’m not really following you.

  • Tim

    Dennis,

    Your first paragraph flatly states that the people at Reasons think that mitochondrial Eve and Y-chromosome Adam are the biblical Adam and Eve when, in fact, they don’t think this for precisely the reason you give in the second paragraph (i.e., that mitochondrial Eve and Y-chromosome Adam didn’t live in the same era). Full stop.

    Rather, the people at Reasons think that the existence of the biblical Adam and Eve best explains why our mitochondrial DNA and Y-chromosome DNA trace back to the respective individual sequences of mitochondrial Eve and Y-chromosome Adam in the first place. Moreover, I can state this confidently because I used to read their material back when I still held to biblical inerrancy some years ago. Full stop.

    In sum, your first two paragraphs not only misrepresent the people at Reasons but falsely portray them as dunderheads who blindly adopted mitochondrial Eve and Y-chromosome Adam as the biblical Adam and Eve without even stopping to see if they lived in the same era. Hence, my complaint against yourself and the reason why I pointed out that the people at Reasons are not only aware of the fact that mitochondrial Eve and Y-chromosome Adam didn’t live in the same era but also have concocted their own idiosyncratic explanation for the relevant discrepancy.

  • AHH

    I think I see where Dennis and Tim are talking past each other.

    While I think RTB is very wrong in this both scientifically and exegetically, the post from Dennis, read literally, says that RTB equates the Biblical Adam & Eve with their Y-chromosome and mitochondrial counterparts.

    But according to Tim in comment #13 they don’t actually equate the two; they would place the Biblical A&E (or at least one of them) as ancestors to these scientific constructs. If that is the case (Tim says he heard Hugh Ross say this; the RTB article at the link I posted (#11) reads like they are being equated but upon close inspection is ambiguous on that front), then the claim in Dennis’ post about RTB isn’t quite true.

    That RTB’s explanation is ad hoc and doesn’t fit the data (especially now that Y-chromosome Adam is further back), and that there are other mistakes in the RTB article (see the comment thread on the Biologos post), doesn’t change that their misguided claim is, according to Tim’s memory, not misguided in quite the same way the post claims it is.
    But one can hardly blame Dennis for missing that nuance, especially since the only written RTB material referenced in this thread, while perhaps leaving enough room for ambiguity to include the explanation Tim reports, on a surface reading is very much in line with the claim Dennis made.

  • Dennis Venema

    Ah, I get it. Sorry Tim, you are correct. As you note, for RTB, the people in question are Eve and Noah. My Bad. I did even know that at the time of writing that post, but somehow that slipped through my editing process. I’ll reword that post. They do claim, as you note, that the pattern is explained with all humans descending from a pair, and that as the main point of the critique despite that unintentional error on my part. They completely avoid the issue of non – Y and non – mitochondrial inheritance (i.e. the bulk of our DNA) in order to do so, and depend on the average evangelical not knowing any better. I’ve explained this all to Rana, in person, at length, and yet RTB sticks to their preferred model.

    Scientifically, of course it’s no help to appeal to the few generations between Adam and Noah to explain the 50,000 vs 180,000 dates. Now that the last common Y-chromosome ancestor is known to be greatly older than mitochondrial eve, the problems for the RTB model are even worse. Now even the average layperson can see that the pattern is wrong (Noah is older than Eve?). I wonder if RTB will even try to address the issue – likely they’ll have to fall back on disputing the methods all together, despite tacitly approving them when they claimed the data went their way.

  • Tim

    Dennis,

    I agree with everything you said in that last comment. Moreover, as I said above, I figured it was an honest mistake on your part.

  • http://www.reasons.org/podcasts/science-news-flash/y-chromosome-discovery-sparks-evolutionary-debate Dennis Venema

    Hi Tim,

    Well, turns out that I am now “correct” – RTB now claims that the common Y chromosome and mitochondrial ancestors are in fact Adam and Eve, not Noah and Eve. There’s an RTB podcast (click my name for the link) where Rana discusses this about 12 minutes in. Still haven’t finished the podcast to see where Rana will go with the new data of the much older Y chromosome sequence, but early hints seem to suggest he’ll disparage the accuracy of the dating methods.

  • Dennis Venema

    … and that’s where he goes, as I thought (to question the accuracy of the methods and cherry pick the part of the range that best suits the RTB model). I wondered if they would also fall back to the bestiality issue, as they have for Neanderthal and Denisovan interbreeding data – and yes, they use that as the fall-back position. So, if the dates eventually don’t go their way, they can claim that this unusual variant is the result of human / animal matings (that leave fertile offspring that then enter the human population).

  • Dennis Venema

    Of course, to be clear, the dates already aren’t going their way, but the point is if they eventually feel they can’t hold on to their preferred dates.

  • AHH

    So RTB is now saying that their literal Adam and Eve, whose sons did agriculture and livestock, lived over 100,000 years ago?
    For hardline Biblical literalists, they sure don’t seem to mind twisting the text beyond all recognition when necessary to preserve their model (their contrived interpretation of the 4th day creation events being another example).

  • Dennis Venema

    Yes, the RTB model would place agriculture and animal husbandry at over 100,000 years ago (!!). For those not following here, there is no evidence of any such thing that far back, not even close. A few years back they opted for Adam at 50,000 years ago, but they’ve pushed his date back to try match up with the (up until very recent) consensus on when Y-chromosome adam lived. Now that we have the much older Y chromosome sequence they’re trying to push it back even farther, to around 140,000 – 200,000 years ago, right to the dawn of our species in the fossil record. So, agriculture at 200,000 years ago? Shows what happens when you’re trying to force fit a model without data to back it up…


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