The in vitro transmission frequency of the tn mutation in the mouse

Male mice which are heterozygous for a recessive lethal mutation ( + /t) transmit the t mutation in non-Mendelian ratios. In the present studies, spermatozoa obtained from + /t males were used to fertilize ova from + /t females in vitro. The frequency of transmission of the t mutation determined from these in vitro studies was compared with the frequency of transmission of this mutation in normal and delayed matings. The data show that the transmission frequency of the t mutation, in vitro, is Mendelian and is the same as the transmission frequency of the t mutation in vivo when matings are delayed until the time of ovulation.