Five of the nine genetically defined regions of mousethaplotypes are involved in transmission ratio distortion

Abstract

SummaryMousethaplotypes have been divided into nine subregions that are each defined by one or more molecular markers. In previous studies, three of these subregions were shown to contain ‘distorter loci’ that interact to effect the transmission-ratio distortion phenotype characteristic of all completethaplotypes. To determine which of the remaining six subregions also play a role in this phenotype, we analysed the accumulated data on transmission ratio distortion from males that carried one of 26 different combinations of two partialthaplotypes. We have obtained evidence for the association of two additional subregions with distorter loci. First, we present further evidence for the existence of a previously postulated distorter locus,Tcd-3, and describe its mapping to the T66C subregion. Secondly, we describe the identification of a new distorter locus,Tcd-4, in association with the subregion defined by the structural gene for theTCP-1 protein. Further studies indicate that two doses of theTcd-4locus are equivalent in effect to a single dose each ofTcd-4and a second distorter locus,Tcd-1. This result suggests that different distorter locus products could have a common mode of action.