The substance of what I was saying doesn’t change.
This is true.
However, Rohde, Olson, and Chang’s Nature paper is a peer-reviewed article. https://www.stat.yale.edu/~jtc5/papers/CommonAncestors/NatureCommonAncestors-Article.pdf? Nature states that Letters are peer-reviewed, and “Modelling the recent common ancestry of all living humans” is published by Nature as a Letter. So this isnkt a blog post, magazine essay, or informal commentary; it is a peer-reviewed research article in a top-tier journal.
Rohde, Olson, and Chang’s Nature paper doesn’t specifically argue for a uniquely identifiable original couple. Read in context, however, it does argue for something highly relevant: if one goes far enough back in time, all living humans come to share the same genealogical ancestral set. The paper is Douglas L. T. Rohde, Steve Olson, and Joseph T. Chang, “Modelling the recent common ancestry of all living humans,” Nature 431 (2004), 562–566.
The opening context is crucial. On p. 562 of the paper, that is, PDF p. 1, the authors clarify that genealogical ancestry proceeds “through both males and females” and includes one’s “parents, grandparents, and so on.” So they are not talking about only mtDNA or Y-chromosome lineages. They are talking about the full human pedigree. That matters because the claim at issue is genealogical: not “who left all the DNA,” but “who really stands in the ancestral tree.”
The central passage is on p. 563, PDF p. 2. The authors write that, beyond the MRCA, there is “a growing percentage of people” in earlier generations who turn out to be common ancestors of the present-day population. They then add that, beyond what they call the IA point, each individual living sufficiently far back is either a common ancestor of all people alive today or of none, and therefore each present-day human has “exactly the same set of ancestors.” The paper is not saying “two ancestors only.” It is saying something broader and more important: all living humans eventually share one and the same genealogical ancestral set.
The paper then places an important limit on the claim, as on p. 565, PDF p. 4, the authors say that if a human group “were completely isolated,” then the MRCA would have to predate the start of that isolation. Shortly afterward, however, they add that no large group is known to have maintained complete reproductive isolation for extended periods, and they even mention the Bering Strait. So the model doesn’t license careless claims, what it does say, clearly, is that if one places the couple far enough back ( before the relevant separations ) universal genealogy remains possible.
The conclusion of the paper confirms exactly this reading: on p. 565, PDF p. 4, the authors write that the most recent common ancestor of the world’s current population probably lived in the relatively recent past, and that a few thousand years earlier “the ancestors of everyone on the Earth today were exactly the same.” But they immediately add the decisive qualifier: this is true in “genealogical rather than genetic terms.” A few lines above, they also explain that a person may receive “little or no actual genetic inheritance” from the vast majority of ancestors living at the IA point. So the paper does not support two exclusive genetic founders; it supports the possibility of universal common genealogical ancestry.
I’m certainly not saying that “this proves one unique original couple”. My conclusion is much more careful: if all living humans share the same genealogical ancestral set, then that large common set includes real men and real women; therefore it is fully compatible with the claim that a real ancient pair, placed far enough back in time, could belong to that shared set and thus be genealogical ancestors of all living humans. The paper doesn’t prove the uniqueness of such a pair, but it certainly doesn’t rule out its possibility, nor does it make it unreasonable. On the contrary, it makes that possibility scientifically intelligible precisely because it shows how deeply human pedigrees interlock.
Put differently: Rohde, Olson, and Chang’s model is incompatible with the claim that “all humans descend genetically only from two people”, but it is compatible with the claim that “all living humans may also descend genealogically from a real ancient pair”, and that distinction is not an external gloss imposed on the paper, it’s exactly what the authors themselves mean by the contrast between “genealogical rather than genetic terms.”
This framework is also consistent with classical Christian teaching about a real primordial event, real first parents, and the transmission of original sin by descent rather than by mere imitation, provided one doesn’t confuse genealogical universality with an exclusive two-person genetic bottleneck.
The orthodox Christian teaching ties universal human solidarity and the transmission of original sin to real descent from the first parents. Science doesn’t prove their original holiness, grace, and sanctity, what it does do, in this case, is remove the objection that such a pair would be biologically impossible.
Long story short: Rohde, Olson, and Chang do not prove a unique and exclusive original couple, but their peer-reviewed Nature article is genuinely compatible with the possibility that a real ancient pair, living far enough back in time, could be genealogical ancestors of all living humans.