Genetic background affects expression of t haplotype in mouse sperm

Abstract

SUMMARYTwo aspects of sperm phenotype were examined for tw32/+ males of the inbred strains C3H and C57BL/6 (B6). Sperm from fertile C3H-tw32/+ males very rarely achieved fertilization in vitro, while sperm from congenie C3H-+/+ males had no such difficulties. The presence of tw32 had no effect on ability of B6 sperm to undergo fertilization in vitro. In fertile hybrid males produced from crosses of B6 and C3H strains, tw32 significantly reduced, but did not inhibit completely, the sperms' ability to fertilize in vitro. The presence of tw32 decreased by a factor of two the frequency of abnormal sperm heads in males of the B6 strain, but doubled the frequency in the C3H strain. Hybrid males resembled the C3H strain in this respect. The presence of T or T2J had no effect on the level of sperm abnormalities in any strain. These results emphasize the importance of genetic background in expression of t haplotypes in sperm, and suggest that tw32 can influence a range of sperm characteristics, by interacting with products of other loci.