Asynchronous activation of parental alleles at the tissue-specific gene loci observed on hybrid trout during early development

By using three genetic markers, the asynchronous activation of parental alleles during embryonic development was studied on interspecific hybrids between the male brown trout and the female rainbow trout. The genetic markers used were lactate dehydrogenase (LDH) A² as well as C subunits and alcohol dehydrogenase (ADH) subunits. Starch gel electrophoresis was utilized. The presence of LDH A² subunits was detected from a very early stage of development in whole embryo extracts. However, up to a few days after hatching (63rd day), A² subunits present were exclusively of the A^2R type derived from the rainbow mother. The coexistence of the products of both parental alleles at this gene locus became evident only at the 70th day. The LDH C subunits which occur only in the retina of the eye as well as the ADH subunits which occur only in liver made their first appearances at the 95th and 150th days, respectively. At these dates, only the maternally derived rainbow subunits were detectable. It took another 40 days for the paternally derived brown subunits to make their appearance.In Duarte, this work was supported in part by PHS grant CA-05138 from the National Cancer Institute, U.S. Public Health Service.