Genetic differences between two allopatric sibling species of the genus Polydora (Polychaeta: Spionidae) from the West Pacific

Abstract

Polydora vulgaris Mohammad, 1972, a commensal borer of the oysters Pinctada margaritifera and Hyotissa hyotis from the South China Sea, was investigated by means of starch gel electrophoresis. Polydora vulgaris and the allopatric sibling Polydora glycymerica Radashevsky, 1993, a commensal borer of the bivalve Glycymeris yessoensis from the Sea of Japan, were compared with respect to their allozymic variation and number of isozyme loci. Interspecific differences in the number of gene loci coding for three enzymes: alanopine dehydrogenase, glucose-6-phosphate isomerase and l-iditol dehydrogenase were revealed suggesting that we are dealing with two valid species. Two different modes of origin duplicate loci in polydorids are dicussed—polyploidization and regional gene duplication. The use of gene number as a character for discriminating between morphologically indistinguishable allopatric polydorid taxa is outlined.