On measuring genetic distance by selection intensity.

A simple selection model (fitness 1, w, w2 for AA, Aa, aa) is employed to change the gene frequency of one population to another. The genetic distance is then defined as d = -log w between the two populations. The distance is symmetrical with respect to the two populations. It is additive: d13 = d12 + d23. The sampling variance of d takes a very simple form. The possible difficulties of using genetic distance in studying evolutionary history have been briefly discussed. The writer means no offence to those who have developed or used the various measures of genetic distance.