Laboratory of Integrative Aquatic Biology, Graduate School of Agriculture Science, Tohoku University, Onagawa, Miyagi 986-2242, Japan
In order to clarify the genetic population structure of sea urchin Strongylocentrotus nudus, microsatellite DNA analysis and mtDNA analysis were carried out for 445 individuals collected from 10 localities around Japan and the Korean peninsula. Overall genetic divergence of S. nudus was very low (Global FST; msDNA=0.0018, mtDNA=0.029) and SAMOVA did not show any clear clustering. Mismatch distributions of mtDNA were monomodal with peaks at 0 to 2, and Tajima's D and Fu's FS also showed significantly negative values. The results show that the recent population expansion (about 5 to 10 thousand years ago) of S. nudus has contributed to the lack of genetic divergence of the present populations.