Intra- and interspecific crosses involving green sunfish (Lepomis cyanellus) and redear sunfish (L. microlophus) were made to produce progeny of each parental species and reciprocal hybrids. The differences in growth rates of different progeny classes were determined and related to their differences in tissue enzyme activities. After one growing season, redear female × green male hybrids showed the greatest growth (average weight gain) followed by that of green female × redear male hybrids, redear and green sunfish. At the end of the second growing season, green female × redear malehybrids had the highest average weight followed by redear female × green male hybrid, redear and green sunfish. Specific activities of different enzymes (malate dehydrogenase, lactate dehydrogenase, glucosephosphate isomerase and phosphoglucomutase) in one or more tissues (skeletal muscle, liver, and eye) also differed among the progeny classes. No significant correlation was observed between growth and the tissue levels of enzyme locus expression. Enzyme activity levels of hybrids tended to be intermediate to those of parental species, whereas growth rates of each hybrid exceeded parental growth rates. Apparently, alterations of gene regulation in the hybrids are exerting different effects upon these morphological and molecular traits.
Couldn't find a pic either.
