Sexual Selection in Mice. IV. Experimental Demonstration of Selective Fertilization

Abstract

One group of 14 albino females of the ST/bJ strain were allowed to mate first with albino males of their own strain and then to black-agouti males of the CBA/J strain. In a second group of 14 albino females, a reverse sequence of matings were arranged. All females were sacrificed and dissected 18 days later. When the albino males had mated first, there were found 113 (95%) albino and 6 (5%) pigmented fetuses. When the black-agouti males had mated first, there were found 88 (70%) albino and 38 (40%) pigmented fetuses. In each experiment the excess of albino fetuses over pigmented fetuses was statistically significant. Various aspects of selective fertilization and its relation to sexual selection are discussed.