Differences in or near the responder region of complete and partial mouse t-haplotypes.

Abstract

SummaryThe transmission ratio distortion seen in males heterozygous for a mouset-complex has been explained on the basis of trans-acting distorter genes, having a harmful effect on a responder gene. Thet-complex form of the responder is relatively resistant to these harmful effects and hence is preferentially transmitted. Animals homozygous for thet-complex responder would be expected to show equal transmission of the two homologous chromosomes, but this is not always so. Studies described in this paper have shown differences among completet's in their transmission when opposite a constant responder carrying partialt-haplotype. In addition, the proximal partial haplotypesth49andtw18, both derived fromtw5but of different lengths, behave differently when opposite a responder. The three central partial haplotypes,tlowH,tlow2Handtlow3H, also differ, in thattlow3Hshows lower transmission thantlowHortloW2Hwhen opposite either wild-type, or another responder, or distorter genes. These results can be explained either on the basis of differences in the responder region of various haplotypes, including the possibility of varying numbers of copies of the relevant sequences, or on the basis of differences in cis-acting (as opposed to trans-acting) distorter genes.