Effects of chimaerism for two T/t complex mutations on sperm function

Mouse chimaeras produced by aggregation of embryos heterozygous for two different recessive mutations at the T/t complex have been analyzed by breeding to explore the basis for the phenomena of male transmission ratio distortion and sterility associated with these genes. Whereas males of genotype t^w2/t^w5 are always sterile, male chimaeras of the type +/t^w2 ? +/t^w5 are normally fertile; furthermore, they transmit each t mutation to the same very high extent seen in ordinary (+/t) heterozygotes. Since spermatogenic cells derived from either the +/t^w2 and +/t^w5 genotypes thus function quite independently of one another in mosaic testes, it can be concluded that sterility, and presumably distorted transmission ratio as well, depends on specific interactions between T/t alleles in diploid spermatogenic cells or their individual meiotic descendants.