A Model of Directional Selection against a Recessive Lethal Allele

Table 20.4 A Model of Directional Selection against a Recessive Lethal Allele Genotype BB Bb bb Frequency 0.25 0.50 0.25 Relative fitness (w) 1.0 1.0 0.0 Survivors after selection (total, 0.75) 0.25 0.50 0.00 Relative genotype 0.25/0.75 = 0.50/0.75 = frequencies 0.333 0.667 0.00 Estimated allele frequencies after natural selection: f(B) = (0.333) + (0.5)(0.667) = 0.667 f(b) = (0) + (0.5)(0.667) = 0.333 Estimated genotype frequencies after reproduction: f(BB) = (0.667)2 = 0.445 f(Bb) = 2(0.667)(0.333) = 0.444 f(bb) = (0.333)2 = 0.111