Interspecific hybrids were produced in the laboratory by crossing male redear sunfish (Lepomis microlophus) with female warmouth (Lepomis gulosus). Approximately three‐fourths of the F1 hybrids were morphologically normal, whereas the remainder possessed a deformity of the lower jaw. This deformity may have been due to a failure of nucleocytoplasmic interactions during development. The reciprocal cross of male warmouth × female redear was subject to complete mortality at the free‐swimming stage. Enzymes, the parental allelic isozymes of which are electrophoretically distinguishable, were chosen as genetic markers. Both of the parentally derived allelic isozymes for malate dehydrogenase and tetrazolium oxidase were synthesized in the adult F1 hybrid. Heteropolymers containing both types of subunits were formed for these two enzymes. Thus, both parental alleles were functional in the hybrid. An esterase isozyme observed only in the redear was absent in the adult F1 hybrid. This result suggests that the synthesis of this paternal isozyme may have been repressed because the egg cytoplasm was incompatible with the paternally derived allele. Maternal allelic repression was apparently observed at the lactate dehydrogenase E locus. The warmouth E locus functioned in the heart tissue so that the two heteropolymers B3E1 and A3E1 were synthesized, but these two heteropolymers were not detected in the redear cardiac tissue or in the heart tissue of the adult F1 hybrid. These results suggest the repression of this maternally derived gene function in the F1 hybrid. The morphologically normal and abnormal F1 hybrids possessed identical isozyme patterns for all four enzyme systems.
ASJC Scopus subject areas
- Animal Science and Zoology