Sustainable genetic civersity in populations of the sika deer

为了研究自然种群遗传多样性水平的控制机制，我们对日本梅花鹿进行了种群遗传分析。首先，我们进行了基于人群的分析。对奈良三重县吉野-熊野地方人口进行了人口结构分析。线粒体和微卫星DNA分析表明，该种群保持了较高的遗传多样性水平。小冈居群也保持了较高的遗传多样性。M比分析表明，两个种群都没有经历瓶颈，种群内的基因流动不受碎片化的限制。研究了遗传多样性水平降低的首岛种群和长崎种群的空间结构。大约三分之一的微卫星位点是在长崎人口中固定的。寿岛马种群由北部亚种群和南部亚种群组成。为了验证亚种群是否真实存在，我们利用微卫星数据进行了聚类分析。通过取个体间的Cavalli-Sforza Edwards距离实现聚类。研究结果清楚地表明，寿多司马种群被细分为两个区域亚种群，它们之间的基因流动受到限制。其次，对金喀山岛人群进行了个体研究。我们的研究表明，金喀山种群保持着较高的遗传多样性，这不能简单地用遗传漂变和突变平衡来解释。我们确定了1989-1997年间在岛上出生的幼鲸的父亲身份，发现并非所有的幼鲸都是研究地点的雄性幼鲸的后代。很明显，在研究人群中发生了群外交配。这可以解释为什么我们在金喀山种群中观察到高水平的遗传多样性。这样的划分将有助于维持小种群的遗传多样性。少

To study the mechanism that controls the level of genetic diversity in natural population, we carried out population-genetic analyses of the sika deer in Japan. First, we conducted population-based analyses. Population structure was analyzed for Yoshino-Kumano local population in Nara-Mie prefectures. Both mitochondrial and microsatellite DNA analyses showed that this population keeps relatively high level of genetic diversity. Sizuoka population was also found to retain high level of genetic diversity. M ratio analysis revealed that both populations have not experienced bottlenecking and gene flow within a population is not restricted by fragmentation. In contrast, we study the spatial structuring of two local population, Shoudosima and Nagasaki populations that have reduced level of genetic diversity. About one-third of microsatellite loci was fixed in Nagasaki population. It has been suggested that Shoudosima population consists of two subpopulations, namely, northern and southern. … More To test whether the subpopulations really exist, we conducted cluster analysis by using microsatellite data. Clustering was made possible by taking Cavalli-Sforza Edwards distance between individual. Our results clearly indicate that Shoudosima population is subdivided in two regional subpopulation and gene flow between them was restricted. Second, we carried out individual-based study in Kinkazan island population. It has been shown by our previous study that Kinkazan population retain high level of genetic diversity, whish can not be explained simply by genetic drift and mutation equilibrium. We determined paternity of the calves born on the island between 1989-1997, and found that not all of the carves were sired by territorial males in the study site. It is obvious that extra-group mating took place in the study population. This would explain why we observed high level of genetic diversity in Kinkazan population. Such partitioning would contribute to the maintenance of genetic diversity in a small population. Less