Characteristics in Two Forms of Hirase's Scallop Volachlamys hirasei : 4. Genetic characters

Abstract

To clarify the taxonomic status of two forms (Awajichihiro and Yaminonishiki) of Hirase's scallop Volachlamys hirasei, genetic characters by isozyme analysis were examined as the fourth report of series studies. Since fitness for Hardy-Weinberg equilibrium by chi-square tests indicated no significance at any polymorphic loci in Awajichihiro form, Yaminonishiki form and both the forms pooled, no evidence that the two forms were distinct reproductive populations was recognized. Also, there were no significant differences between the two forms in the values to indicate genetic features and allelic frequencies of the 24 loci examined. The genetic distance (D value) between the two forms indicated 0.0002, being in the level below inter-local population or the same species. The results strongly suggested that the Awajichihiro and the Yaminonishiki forms belong to a single reproductive population, namely the same species, and the morphological variabilities are regarded as phenotypes of the genetic polymorphism. The taxonomic status was decided as follows : Hirase's scallop (Awajichihiro-gai) Volachlamys hirasei (Bavay, 1904) Awajichihiro form V. hirasei var. awajiensis Yaminonishiki form V. hirasei var. ecostata