遺伝からみる日本のウミガメ類の集団構造

摘要

The dynamics and migrations of sea turtle populations is estimated from the information on the genetic diversity and population structure. In nesting populations of green turtle (Chelonia mydas) in Yaeyama Islands, high values of genetic diversity resulted from divergent haplotypes of mitochondrial DNA (mtDNA). The phylogenetic relationship of haplotypes indicated historical introgressions by indi-viduals with divergent haplotypes both from Pacific colonies and Indian and Southeast Asian colonies, suggesting that Yaeyama nesting populations have historically emigrated from divergent tropical colo-nies. For feeding populations, patterns of mtDNA variation were used to analyze genetic population structure and stock composition of green turtles. The results indicated that a foraging aggregation around Yaeyama Islands is dominated by animals from various rookeries, Yaeyama, Ogasawara, Micronesia, and Papua New Guinea (PNG) with occasional migration from other rookeries including eastern Pacific re-gions. On the other hand, a reanalysis of other regional feeding aggregations of Japan indicated that contribution from Micronesia and PNG becomes smaller as the current flows downstream. The regional differences in population structures suggest the need for regionally varying conservation strategies.