What Became of the Genetic Challenge to Adam and Eve?

[John_Harshman]

Did you actually say this?:

Indeed, as Swamidass observes, we know that at some point in the past the number of human beings goes to zero and therefore to fewer than 10,000 individuals. In thinking otherwise, Venema is guilty of a crucial equivocation between “ancestors” and “humans.”[8] Even if the ancestral population of hominins leading to humans remains constantly above several thousand, it does not follow that there were not at some time exactly two humans who emerged within that population. It is entirely possible that at some time in the past, the total number of humans was exactly two, even though the total population of hominins at the time was much greater. The descendants of these early humans might or might not have interbred with their non-human contemporaries. If they did, then the founding couple would not be our sole genetic progenitors, for outsiders would have had genetic input into the human race. On the other hand, if such interbreeding never occurred, the founding couple would be the sole genetic progenitors of the human race, there being no outside input. In either case, there could have been an original founding pair.

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.)

So if it could be shown that there are more than four allele lineages exhibiting trans-species variation, then we should have strong evidence against an originating human pair. But apart from an outdated study by Francisco Ayala, there is no evidence for this.

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

Swamidass notes that the particular gene studied by Ayala is “one of the genes with clear evidence of convergent evolution.

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

Swamidass points out that a founding couple could have been heterozygous, each carrying two different alleles at any locus of their chromosome pairs, for a total of four alleles between the two of them for any locus to be passed on to their descendants.

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.