Selection is the process that dictates which individuals become parents and how prolific the parents will be. Consider a deleterious recessive condition that confers 40% reduction in the viability of homozygous recessive genotypes (s = 0.40), which could occur through reduced survival, reduced fertility, or some combination of the two.
|Fraction removed due to selection||0||0||s = 0.40|
|Fraction remaining after selection||1||1||1 – s = 0.60|
Assume that the A allele frequency is 0.850 (and therefore the a allele frequency is 0.150) in the progeny generation and that the progeny were produced from random mating.