Genetic population structure of Japanese sardinella Sardinella zunasi around Japan.

The population structure of Japanese sardinella Sardinella zunasi around Japan was examined based on complete nucleotide sequences of the mitochondrial control region. Phylogenetic analyses revealed four major lineages (A–D). The frequency of lineage A was higher on the Pacific coast, in the Seto Inland Sea, and on the Sea of Japan coast of Kyushu, while the frequency of lineage B was higher on the Sea of Japan coast of Honshu and in Ariake Sound. The frequency of lineage C was much lower than that of lineages A and B at all nine localities in Japan. Lineage D was detected only in Ariake Sound and the Seto Inland Sea, being considered to be a continental relict. The current distribution pattern of S. zunasi was indicated to be constructed by secondary contact among those four lineages, each having different evolutionary history. Hierarchical analyses of molecular variance indicated S. zunasi around Japan to be structured into three units: (1) the group of the coast of Kyushu, including Ariake Sound, and the Pacific coast south of the Izu Peninsula, including the Seto Inland Sea, (2) the Pacific coast north of the Izu Peninsula, and (3) the Sea of Japan coast of Honshu. [ABSTRACT FROM AUTHOR]