Genetic population structure of the mudskipper, Periophthalmus modestus, in Japan inferred from mitochondrial DNA sequence variations.

Abstract

The geographical distribution of mitochondrial DNA (mtDNA) haplotypes in the Japanese mudskipper, Periophthalmus modestus, were investigated. Twenty-one mtDNA haplotypes were obtained from 48 individuals representing 7 populations (5 from major Japanese Islands and 2 from the Ryukyu Islands), some haplotypes being shared among the 5 Japanese populations. Each Ryukyu population (Tanegashima and Okinawajima Islands) had endemic haplotypes. The analysis of molecular variance (AMOVA) and nested clade parsimony analysis (NCPA) indicated that the Ryukyu and Japanese populations were isolated from each other, whereas the mtDNA phylogeny indicated that the Ryukyu population haplotypes were included within the clades of the Japanese haplotypes. These results suggested that the duration of isolation of the Ryukyu populations from those of the major Japanese Islands was insufficient for the establishment of reciprocal monophyly of the mtDNA phylogeny.