Inheritance of Muscle Proteins in Hybrids Between the Redside Shiner (Richardsonius balteatus) and the Peamouth Chub (Mylocheilus caurinum)

Abstract

Selected muscle proteins were examined in artificially reared redside shiners, Richardsonius balteatus, peamouth chubs, Mylocheilus caurinum, and in their F1 and backcross hybrids to determine if they would be useful in identifying suspected natural hybrids. In reference to the proteins studied, Mylocheilus possesses a single zone designated "3"; Richardsonius also possesses a single zone designated "1," but of slower mobility. Artificially reared F1 hybrids possess, in addition to both parental zones, a unique zone designated "2" which was assumed to be composed of components of zones 1 and 3. Some naturally occurring individuals suspected of being hybrids on the basis of morphological characters possessed a pattern identical to that of the experimentally produced F1 hybrid (zones 1, 2, 3). Other suspected hybrids possessed either zones 1 and 2 or zones 2 and 3. These types of pattern corresponded to some of those produced by backcrosses to Richardsonius and Mylocheilus, respectively.The presence of both parental protein zones in the F1 hybrid indicates that each polypeptide can be synthesized when only half the alleles of each parent is present. This characteristic of codominance can be useful in identifying suspected hybrid offspring of parents having different protein zones.Evidence is presented which supports the hypothesis that the proteins in question are genetically controlled by two loci, A and B, each of which exists in two allelic forms.