Genetic dissection of clonally inherited genomes of Poeciliopsis: II. Investigation of a silent carboxylesterase allele.

According to the ratchet mechanism hypothesis, deleterious mutations should accumulate in clonal genomes of unisexual fish of the genus Poeciliopsis. This study defines one such mutant, a silent carboxylesterase allele (ES-5 degrees) which is found in the heterozygous condition in a particular population of P. monacha-occidentalis. An antiserum to purified Poeciliopsis carboxylesterase cross-reacts with the gene product of the Es-5 degrees allele upon immunoelectrophoresis. This finding of cross-reacting material associated with the Es-5 degrees allele provides a useful marker for the breeding of a carboxylesterase deficient strain.