What Became of the Genetic Challenge to Adam and Eve?

Does genetics challenge a single-couple origin to humanity? William Lane Craig explains how we found that this challenge was an illusion.

Does population genetics challenge a single-couple origin to humanity? In early 2017, Dr. Richard Buggs raised scientific concerns about Dennis Venema’s book, Adam and the Genome . His concerns were distinct and addition to concerns that Dr. Swamidass raised that year too. In late 2017, Dr. Venema responded at BioLogos, and a conversation grew. Together, several scientists did indeed find several fundamental mistakes with Dr. Venema’s argument against a single couple origin of humanity. Eventually, in 2020, even BioLogos began backing away from Venema’s scientific claims. In this article, Craig summarizes for a lay audience the science behind this shift. For technical readers, the forum thread for this article expounds and clarifies his summary with greater precision.

@moderators will govern this thread more tightly so we can keep it brief and to the point with any specific questions raised by scientists about this article. Some of WLC’s usage of terms (e.g. “genetic diversity”) will be somewhat confusion, and also it is possible that there is trans-species variation of more than 4 lineages. His basic summary, nonetheless, seems correct, though targeted at a lay audience.

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Did you actually say this?:

It seems to incorporate what one might call the “first speaker of French” fallacy, having new species arise by saltation, simultaneously in two individuals of opposite sex. Assuming that there is some discrete moment at which the human species begins does violate everything we know about speciation. (Unless you’re referring to “textual humanity”, which Craig clearly is not.)

We’ve talked about that. Craig is wrong. You can reject the evidence, but you can’t claim it doesn’t exist.

We’ve talked about that too. I don’t believe the convergence required is anything like the sort in that paper you cited.

Technically true. But it would require a major miracle, nearly as large as de novo creation of the couple. Nobody is that heterozygous. No two individuals are that mutually heterozygous. I don’t see the point of postulating that miracle to save you from a different one.

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3 posts were split to a new topic: Was there a “first French speaker”?

I did claim this in 2017, so he is correct in reporting it. This is one of the points I am doing a detailed look and aim to clear things up soon.

I want to explore this. What level of heterozyocity do you think this implies? Can you produce some calculations or evidence for an AE at 0.5 Mya or 1 Mya?

I’m not sure what the heterozygocity required would be any different than what we observe in humans today. Recall that many variants would enter the population by mutations after Adam and Eve.

Craig is hypothesizing that both A&E were heterozygous at every polymorphic site, from what I can tell. Or he’s claiming that you said that. What did you actually say?

He is imperfectly summarizing my argument. I think it is absurd to think AE were heterozygous at every site, but nothing in the evidence demands this. Nothing in his model demands this either.

Moreover, he is meaning this in opposition to the idea that AE are homozygous clones of own another. That would be a miracle.

Perhaps that’s what he meant to say, though what he actually said seems clear enough. He’s using original heterozygosity to explain current allelic diversity. Ah, well, the heterozygosity isn’t the main thing wrong with his scenario.

I don’t think that there is any evidence for an A&E at any age, in the sense of a couple who are the sole ancestors. Nor is there any evidence for them when you consider only genetic ancestors. We do expect that at each small region of the genome there will be an Adam or an Eve, at some age about 1 mya, but there is no reason to expect those to be the same people for every region of the genome.

And consistency with religious doctrines is not evidence in this inference.

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Oh I agree with this. Isn’t that clear? I personally don’t think the human population was just a single couple 700 kya, and I did not find any evidence to support it.

That is something different. If there was a single couple bottleneck we would not expect MRCA of autosomes at that bottleneck. MRCA for many parts of the autosome could have been much more ancient than the bottleneck.

It is a subtle point, but it’s important for this question.

I agree. Never said it was. The question is different. Is there evidence against this doctrine when considered across a large range of auxillary hypotheses?

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The bottleneck, whose presence is not indicated by any genetic evidence, though perhaps demanded by theological considerations, has to be very short for that to be true.

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That sounds about right. I agree there is not evidence for it, at least as far I can tell.

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