Drift & Selection on rare recessive alleles with weak selective dis-advantage in finite populations
(N = 100, f(B0) = 0.005; W0 = W1 = 1.00, W2 = 0.99)
Trajectories of a weakly deleterious recessive (s = 0.01) rare mutant allele in multiple populations (N = 100 @) from an initial single copy f(B) = 1/200 = 0.005. Most replicates go to f(B) = 0 within 25 generations: six remain polymorphic at t = 100 generations, three at t = 150, and only one at t = 300 generations. One population goes to fixation, f(B) = 1.0, just short of t = 250 generations, despite its selective disadvantage. Note that s < 1/2N.
Figure & Text material © 2025 by Steven M. Carr