But this is precisely the question that I am interested in, regardless of Dennis never meaning it. I want to know about our homo sapiens ancestors. Otherwise this has absolutely no relevance to the issue of Adam and Eve at all.
All I have seen from your own scientific bottleneck testing is that there’s no bottleneck going back even 500,000 years which could remotely be identified as evidence that either homo sapiens or our ancestors were bottlenecked down to a single pair.
I don’t see how this establishes your claim.
But it’s incredibly unlikely that it was only one person who started it; it was more likely to be a group of people. I just don’t find other scientists saying what you’re saying. I find them saying things like “There was no first human”. And they say things like this.
The first thing you see is obvious: our ancestors went through two different phases of population “bottlenecking” (constriction): one occurred about three million years ago, when a large population declined to around 10,000 individuals. The authors note that while this may reflect population size decline associated with the origin of hominins after our split with the lineage that produced modern chimps, they also say that this could be an artifact of ancient genetic polymorphisms maintained by natural selection.
The second bottleneck is the one of interest, for it’s the one associated with a reduced population size as humans left Africa. For the Chinese, Korean, and European genomes, effective population size fell from about 13,500 (at 150,000 years ago) to about 1200 between 20,000 and 40,000 years ago. Now this is the effective population size, almost certainly an underestimate of census size, but that only makes the problem worse: we never went through a bottleneck of anything near two individuals, as the Biblical Adam-and-Eve story suggests. This, of course, means that theologians have to scramble to save that story, turning it, as always, into a “metaphor”. (In science, a falsified hypothesis gets tossed on the scrap heap; in religion, a falsified hypothesis becomes a metaphor.) And it also suggests that Jesus died for that metaphor.
But enough of Biblical exegesis. While the bottleneck for non-European populations was probably associated with a group leaving Africa and subsequently colonizing the world, we also see a somewhat less severe bottleneck in the African samples: from about 16,100 people about 100,000-150,000 years ago to 5,700 about 50,000 years ago. It’s not clear why the populations in Africa bottlenecked as well.