Studies on phylogeographic changes and mechanisms of diversification of the Hokkaido sika deer populations using ancient DNA analysis

本研究的目的是分析北海道考古遗址出土的梅花鹿遗骨的古代DNA，并与现代梅花鹿种群的遗传数据进行比较，揭示其种群结构、系统地理历史和多样性机制的变化。我们从不同年龄的鹿遗骸中鉴定出许多线粒体DNA(MtDNA)单倍型(来自绳文期、Epi-绳文期和Ainu文化期)以及北海道不同地区的鹿。这些单倍型包括现代梅花鹿中没有发现的新单倍型。从更古老的考古遗址中，发现了更多的新单倍型。包括线粒体DNA在内的现代本州梅花鹿的分子系统发育研究表明，北海道梅花鹿的单倍型在古代和现代之间形成了一个共同的簇。结果表明，自柔门时代以来，北海道梅花鹿种群的遗传多样性一直在减少，在过去的北海道，由于环境的变化，它们经历了种群的大规模迁移和种群规模的动态变化，如瓶颈。此外，我们还对目前梅花鹿的线粒体DNA进行了调查，并与10年前采集的样本进行了比较。结果，我们发现在过去的十年里，梅花鹿种群从北海道东部向西部迁移。

The purposes of the present study are to analyze ancient DNA of sika deer bone remains excavated from archaeological sites in Hokkaido, and to reveal changes of their population structures, phylogeographical history, and mechanisms of diversification, compared with genetic data of the modern populatiuons of sika deer. We identified many haplotypes of mitochondrial DNA (mtDNA) from deer remains of various ages (from the Jomon, Epi-Jomon, and Ainu Culture Periods) and of various areas within Hokkaido. The haplotypes included new ones which had not been found from modern sika deer. From more aged archaeological sites, more new haplotypes were found. Molecular phylogenetic studies including mtDNA of modern Honshu sika deer demonstrated that haplotypes of the Hokkaido sika deer form a common cluster between ancient and modern ones. The results show that genetic diversity in the Hokkaido sika deer population has been reduced since the Jomon Period, and that they have experienced large movement of populations as well as dynamic changes of population sizes such as bottlenecks through environmental changes in past Hokkaido. In addition, we investigated mtDNA of present sika deer and compared the data with those of samples collected ten years ago. As a result, we found the movement of the sika deer populations from eastern to western parts of Hokkaido during the last ten years.