Genetic Variation in Marine Molluscs

Abstract

Starch gel electrophoresis was carried out to survey genetic variation in 25 species of marine molluscs. The gel phenotypes for 19 enzymes and muscle proteins are described. Genetic variation measured as the proportion of polymorphic loci varied from 0.190 to 0.667 with a mean of 0.412±0.030, as observed heterozygosity from 0.059 to 0.216 with a mean of 0.129±0.009, and as expected heterozygosity from 0.060 to 0.250 with a mean of 0.147±0.011. Marine molluscs are generally more variable than marine teleosts.
An excess of homozygotes was observed at many loci in most species of molluscs. Such a phenomenon has not been observed in marine teleosts. Possible explanations for this observation are discussed.