Sunday, February 26, 2006
Today's London Sunday Times has an article here about a forthcoming theory on the evolution of blondeness in Northern Europe. The theory is that blondeness become common around the end of the last Ice Age as a result of strong sexual selection on females. Food was short and men had to go on long arduous hunting trips. A lot of them died, leaving a surplus of females, so there was pressure for females to attract mates, resulting in variant hair colour, etc., being selected.
The theory sounds to me like what is technically known as 'a load of bollocks', but hey, what do I know? Actually, what I do know is that women, unless they are very old or seriously ugly, have no difficulty in obtaining mates - all they have to do is to be available. The theory might be more plausible if the society were strictly monogamous, and women found it difficult to get a husband to provide for their children, but very few hunter-gatherer societies are strictly monogamous, least of all if there is a surplus of women.
Added: I see from a Google search that the theory is not that new. The author, Canadian anthropologist Peter Frost, has been touting it in one form or another for some time. I should also say that even in a polygamous society sexual selection on females might operate through the quality of husbands, but I guess this would be a comparatively weak force, and what is needed for the theory is unusually strong selection.
Addendum from Razib: Remember, "beware of British newspapers." The story concludes with this old false story from 3 years ago:
John Hawks has more. A "recessive" trait like blondness will disappear when the frequency is so low within a panmictic population that the expectation of alleles conferring blondness coming together becomes very low. If you think of it as a monogenic trait (say on MC1R), then it is just a matter of Hardy-Weinberg, p2 + 2pq + q2 = 1, so if q was the frequency of the blonde allele than frequency of blondes would go to q2. As it is, I don't see the process of panmictia in the near future....
Update II OK, I'm going to cut & paste my comment here so everyone sees it. For what it's worth, Dienekes has addressed Frost's thesis and offers his own counter-argument.
Here is the link to the abstract.