Gene dosage effects on transmission ratio distortion and fertility in mice that carrythaplotypes

Abstract

SummaryCompletethaplotypes can be transmitted at distorted ratios from heterozygous +/tmale mice as a consequence oft-specific alleles at a series oft complex distorterloci (Tcd-1tthroughTcd-4t) and at complex responderlocus. Partialthaplotypes that lack theTcd-2tallele cannot be transmitted at the very high ratios characteristic of completethaplotypes. The breeding studies reported here tested the possibility that the absence ofTcd-2tcould be compensated for by the presence of double doses of otherTcdtalleles. The results indicate that a double dose ofTcd-4talone will not work, but that a double dose of bothTcd-1tandTcd-4tcan promote a very high transmission ratio in the absence ofTcd-2t. These results suggest that the extent to which transmission ratios are distorted is dependent upon the absolute level of expression of the individualTcdgenes. Further studies of genotypic effects on transmission ratio distortion, as well as fertility, lead to the suggestion of a fiftht complex distorter(Tcd-5) locus withinthaplotypes.