Genetic variation and differentiation in six local Japanese populations of the sea-urchin, Anthocidaris crassispina: Electrophoretic analysis of allozymes

Abstract

1. 1. Protein variation, levels of heterozygosity, and inter-locality genetic differentiation were studied in six local Japanese populations of the sea-urchin, Anthocidaris crassipina , by electrophoretic analysis of 18 different enzymes. 2. 2. The proportion of polymorphic loci ( P ) was in the range 7.7–23.1% with a mean of 19.2%, and the average heterozygosity per locus ( H ) in the range 2.8–8.8% with a mean of 6.3%. These values are comparable to those observed in marine invertebrates from shallow water, but are considerably lower than those from the deep-sea. 3. 3. Of 18 enzymes examined, the glucose metabolizing enzymes were less variable than the non-glucose metabolizing enzymes, as already observed in many other animal species. 4. 4. The Nei's genetic identity values between six local populations of the species ranged from 0.933 to 0.992 with a mean of 0.963. These values fall within the range of those observed in conspecific local populations of various animal species. 5. 5. The biochemical dendrogram showing genetic relationships among six local populations of the species demonstrated that the marginal populations are a little genetically differentiated from the populations in the middle zones of distribution.