Antagonistic pleiotropy and genetic polymorphism: a perspective

Antagonistic pleiotropy, in which reproduction and viability counter each o ther, appears to be widely thought of great significance in life history th eory and the evolution of senescence. However, the conditions for maintenan ce of polymorphism by antagonistic pleiotropy are quite restrictive. This i s particularly so when there is no reversal of dominance for different trai ts, sex-limited expression of fitness components, finite population size or inbreeding. Furthermore, when antagonistic pleiotropy is compared with oth er mechanisms of balancing selection, it appears to. have more restrictive conditions for the maintenance of polymorphism. Although these theoretical findings do not preclude the presence of loci that exhibit antagonistic ple iotropy, because it appears so unlikely that antagonistic pleiotropy is an important factor maintaining polymorphism, empirical evidence suggesting an tagonistic pleiotropy as the factor maintaining polymorphism should be care fully scrutinized.