The Population Genetic Structure of Tetranychus kanzawai Kishida (Acari: Tetranychidae) in Northern Hokkaido, Japan, as Estimated Using Microsatellite Polymorphism

Abstract

We examined the genetic structure of Tetranychus kanzawai populations occurring in northern Hokkaido, Japan, and gene flow among the populations using microsatellite DNA markers. Our intrapopulation analysis found that the genetic diversity within each population was small, whereas our interpopulation study revealed that the populations were genetically isolated, though a few population pairs were genetically close. The results show that in this study area, T. kanzawai maintained its population mainly by inbreeding, without frequent interpopulation gene exchange. As a consequence, the genetic diversity within each population was small but the genetic differentiation among populations was large. マイクロサテライトDNAマーカーを用いて，北海道北部におけるカンザワハダニ個体群の遺伝的構造，およびそれらの個体群の遺伝子交流について調査した．個体群内・個体群間での遺伝的変異を解析したところ，個体群内での遺伝的多様性は小さかった一方で，個体群間での遺伝的分化は大きく，遺伝的に近縁な個体群はわずかしか認められなかった．つまり，本調査地では，カンザワハダニは主に同系交配によって個体群を維持し，個体群間の遺伝子交流はほとんどないと考えられた．その結果，個体群内の遺伝的多様性は小さい一方で，個体群間の遺伝的分化は大きくなっていた．