Dear @DennisVenema
I am very grateful to you for your response to my original email and blog about the possibility of a bottleneck in the human lineage, and for the discussion that we have had in blogs and on this forum. Your work has helpfully highlighted an area of misunderstanding of current science that is probably shared by many, and it has been extremely informative to all of us to debate this issue and establish what current genomics does and does not show about past human population sizes. All of us have learned a great deal from this.
It is clear to me, as someone who has followed this debate closely and participated in it, that you (like me) now understand the field a lot better than you did before 2017. When you wrote Adam and the Genome you clearly believed that genomic evidence – from the case of the Tasmanian devils, from PSMC analyses, from the Tenesa et al study of linkage disequilibrium, and from allele counts – meant that it was almost impossible that humans had ever passed though a bottleneck of two since diverging from chimpanzees. You left your readers in no doubt about this.
In contrast, your more recent contributions on this forum show that you have now realised that the evidence that you cited in Adam and the Genome does not support this claim. You now realise that the studies you cite did not test a single-generation bottleneck of two. Your new understanding is clear to me as someone who has followed the discussion on this forum in detail, and weighed up what you have said and what you have not said, and what you have implied. Please do correct me if I have misunderstood you and I am drawing a wrong conclusion, as I have had to “read between the lines” in places to come to the conclusion that you realise that every one of these lines of evidence does not support the claim.
Assuming that I have understood you correctly, I think it is my responsibility to encourage you to make a clear public statement correcting what is erroneous in Adam and the Genome. I do this on behalf of readers of Adam and the Genome who will not have the time to read through the the debate on this forum (which is now much longer than chapter 3 of your book), but who are honestly seeking to understand what current science says and does not say about human population history. Not only will this be of service to your readers, but your reputation as reliable communicator of science will be enhanced by such a statement.
Yours sincerely,
Richard