As my own review of Nicholas Wade’s book suggested, his treatment of genetics has many deep and fundamental problems. And as my blog post noted, many others have called some of those out. I want to call out here a particularly clean such account, which came from evolutionary biologist Michael Eisen a few weeks ago. He cuts right to the nut of one of Wade’s most central and dangerous errors:
It turns out to be far easier to demonstrate that there has been a fair amount of recent natural selection acting on the human population, than it is to pinpoint specific examples, or to rigorously evaluate specific hypotheses. The reason is that different types of evolution (drift, positive selection, purifying selection) leave different fingerprints in the genome, and we can use these to estimate how prevalent each of these forces has been in human history, and, to a lesser extent, identify regions of the genome that have been subject to certain types of selection.
But the effect of specific examples of selection are almost always weak – especially the kinds of transient selection affecting relatively small groups of people on which Wade hangs his speculation. Furthermore, while natural selection leaves a signal behind in the genome, the signal is primarily that it happened – it’s much more difficult to precisely identify what was being selected, let alone why or how.
Knowing that natural selection has occurred, in some cases recently, but being unable to be more specific leaves a huge void – and it is into this void that Wade has inserted himself.
And a bit later:
In making the leap from the broad to the specific – from signature of natural selection in the human genome to explanations of the industrial revolution, Jewish Nobel Prizes and political turmoil in Africa and the Middle East – Wade tries to paint himself as a courageous scholar, going places with modern evolutionary biology that scientists WILL not go. But the truth is that scientists don’t go there, not because we are afraid to, but because we CAN’T. The data we have before us simply do not allow us to reconstruct human evolutionary history in this way.
from Michael Eisen’s On Nicholas Wade and the blurring of boundaries between science and fantasy, which I urge you to read whole.
