Sterility in mutant (tLx/tLy) male mice. III. In vitro fertilization.

Mice which are heterozygous for two complementary lethal t mutations (t6/tw32) exhibit complete male sterility. Experiments have been conducted to determine if spermatozoa from these heterozygous males can fertilize oviducal ova in vitro. The experiments have been designed so that specific barriers which are present during in vivo fertilization can be sequentially removed and the fertilizing ability of the spermatozoa tested after each barrier is eliminated. Our results show that spermatozoa from t6/tw32 males are unable to effect fertilization even after all of the barriers normally imposed by the female reproductive tract have been removed.