Were huge ancient lakes refugia for fishes distributed in Mogami River System ?

最近的地质资料表明，在400 - 600万年前，在现代最上河系统的上游和下游周围形成了两个巨大的湖泊。对可能在古湖泊周围进化的7种鱼类进行了群体遗传学分析，探讨了古湖泊对鱼类进化的影响。七个物种中有两个可能是在古代湖泊周围形成的。另外3个种的遗传结构在最上河与邻近河流种群之间或在最上河系上下游种群之间存在差异，表明古湖泊的地理隔离影响了它们的遗传分化。在其他两个物种，独特的遗传结构没有识别种群之间。相模川群体与最模川群体相比，通过显著引入来自不同水系的个体无法进行明确的遗传分析。

The recent geological data suggests that two huge lakes had developed around the upper and lower reaches of recent Mogami River System during 4 - 6 million years ago. We conducted population genetic analyses of seven fishes that might be evolved around the ancient lakes, and discussed the influence of ancient lakes for their evolution. Two of the seven species had been probably speciated around the ancient lakes. In other three species, genetic structures were different between Mogami and adjacent river populations or between the upper and lower reach populations in Mogami River System, suggesting that geographical isolation by the ancient lakes had affected to their genetic differentiation. In other two species, distinctive genetic structures did not recognize between populations. In Sagami River populations to compare with Mogami River populations, clear genetic analyses could not do by remarkable introduction of individuals derived from different river systems.