Can't have genetic drift without the other....

Just a quick review about some issues that I assumed implicitly in my post where I took issue with genetic drift as a force for population variation. It isn't like genetic drift can't result in variation...but the researcher seemed to be pointing to founder effect which would homogenize alternative populations and "fix" them into alternative states. For founder effect to really work you need to reduce the effective population size and squeeze genetic polymorphism out of the gene pool. Consider the equation for decline in heterozygosity^1: Ht = (1 - 1/(2N))^tH0 Where H0 is the intial heterozygosity and t is measured in generations. It seems clear that as N approaches infinite there won't be a change, random genetic drift will not sift out the variation from the population because the sampling process is too weak of a force. In contrast, a low N will result in rapid reduction in heterozygosity, ...