Assortative mating in mice and the incest taboo

FEMALES from some inbred strains of Mus musculus, in a state of induced oestrus, when allowed to choose between a male of their own strain and another of a different strain, prefer to associate and mate with males of the different strain. This phenomenon was studied by Mainardi¹ in the C57BL and Swiss strains, and by us (ref. 2 and unpublished results) in the strains BALB/Ibg, DBA/Ibg, C57BL/Ibg, C57BL/J and C3H/J. Our study suggested the existence of a polymorphism for female mating preference, since females from the BALB/Ibg and C3H/J strains mated at random. Observations of the behaviour of females reared with foster fathers showed that a major determinant of mating preference is a "paternal effect". DBA/Ibg males, due to their genotype, provide social stimuli which induce a tendency in their daughters for mating preference for unlike males, whereas BALB/Ibg males do not induce any tendency for mating preference in their daughters.