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Social selection in human populations: Protected polymorphism of deleterious alleles with incomplete penetrance
Author(s) -
Yokoyama Shozo,
Crow James F.
Publication year - 1987
Publication title -
genetic epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.301
H-Index - 98
eISSN - 1098-2272
pISSN - 0741-0395
DOI - 10.1002/gepi.1370040307
Subject(s) - penetrance , allele , genetics , biology , selection (genetic algorithm) , polymorphism (computer science) , evolutionary biology , gene , phenotype , artificial intelligence , computer science
Population dynamics of two alleles, A 1 and A 2 , at a locus under social selection have been studied by considering incomplete penetrance of the three genotypes. A social selection model is constructed by assuming that the fitness of an individual is determined by his or her own phenotype as well as parental phenotypes. For both multiplicative and additive fitness models, sufficient conditions for a protected polymorphism depend on the reduced fitness of affected individuals (γ), the reduced fitness of all individuals resulting from affected parents (β), and the penetrance probabilities, f 1 , f 2 , and f 3 , for the three genotypes, A 1 A 1 , A 1 A 2 , and A 2 A 2 . These conditions reduce to two biologically important cases: 1) f 1 < f 2 > f 3 and β < −γ/(1 − γ) and 2) f 1 > f 2 < f 3 and β > − γ/(1 − γ), and the most common form of the equilibrium frequency of the allele A 2 is given by ( f 1 − f 2 )/( f 1 − 2 f 2 + f 3 ).