Fig. 2.

Simulation of allele frequency change over time for a scenario of allele T into Africa a) an initial frequency of 0.001 similar to the current frequencies and fitness of extreme selection at 1.4 a migration rate of 0.4 and population of 100 effective individuals, analysis shows that even with such high selection/fitness values, complete fixation without drift required 300 generations b) with more realistic fitness measures at 1.25 fixation and near fixation required 500 generations to fixation c) with a frequency of allele T approaching the present frequencies (0.0001) which is more comparable with the present values will require 1400–1600 generation to reach fixation.