THE INHERITANCE OF AN EMBRYONIC LETHAL MUTATION IN A SELF-REPRODUCINGTERRESTRIAL SLUG, DEROCERAS-LAEVE

A new lethal developmental mutation (EZL-1, embryonic zygotic lethal-1 ) in Deroceras laeve was used as a genetic marker to determine whether self-reproduction is by parthenogenesis or self-fertilization. An ave rage of 25.7% of the progeny of individuals (N = 38) apparently hetero zygous for the mutation exhibited the EZL-1 lethal phenotype, a result that can only be explained if reproduction is meiotic. Histological s ections of a fertile slug revealed the presence of both sperm and eggs in the gonad, consistent with self-fertilization, rather than parthen ogenesis. In addition to EZL-1, other developmental defects were obser ved in progeny.