ns 08-06

Fixation of a rare allele with weak selective advantage in finite populations


Trajectories of a weakly advantageous (s = 0.010) novel mutant allele in multiple populations with N = 100 @. The allele goes to fA = 0 within 50 generation in most replicates: despite their selection advantage, only two go to fA = 1. Note that this stochastic result is slightly greater than the deterministic numerical expectation for selectively neutral alleles at initial f(A) = 2/200 = 0.01. Note also that one population drifts to f(A) = 0.4 before loss: the expected deterministic trajectory is insufficient to overcome stochastic genetic drift in a small population.


Text material © 2021 by Steven M. Carr