To investigate the species composition and genetic characteristics of Far Eastern daces, genus Tribolodon, in the Tama River, Japan, partial DNA sequences of the mitochondrial DNA control region were compared among specimens from the whole river system. Specimens of Tribolodon hakonensis (n = 257) and Tribolodon brandtii maruta (n = 193) were examined in this study. Inconsistencies in species identification according to genetic and species-specific morphological traits, i.e., breeding color and cephalic lateral line system, were found between some sympatrically distributed specimens (17/450; 3.8%), indicating possible hybridization between T. hakonensis and T. brandtii maruta. The two species were sympatrically distributed in the lower reaches, whereas T. hakonensis solely appeared in the upper reaches and headwaters. In T. hakonensis, we found obvious genetic divergence between the lower and upper reaches, suggesting reproductive isolation related to alternative migration patterns of anadromous and river-resident forms, respectively. Further, it is suggested that native and introduced T. hakonensis populations coexist in the lower reaches and headwaters, whereas the former solely inhabit, or are dominant, in the upper reaches.

中文翻译：

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通过线粒体 DNA 分析推断出日本多摩河系统中原生和引进的远东 daces，属 Tribolodon

为了研究日本多摩川的远东鲱属的物种组成和遗传特征，在整个河流系统的标本中比较了线粒体 DNA 控制区的部分 DNA 序列。在这项研究中检查了 Tribolodon hakonensis (n = 257) 和 Tribolodon brandtii maruta (n = 193) 的标本。在一些同域分布的标本（17/450；3.8%）之间发现根据遗传和物种特异性形态特征（即繁殖颜色和头侧线系统）进行物种鉴定的不一致，表明 T. hakonensis 和 T. hakonensis 之间可能杂交。布兰蒂玛鲁塔。这两个物种在下游同域分布，而T. hakonensis仅出现在上游和上游。在 T. hakonensis 中，我们发现下游和上游之间存在明显的遗传差异，这表明生殖隔离分别与溯河和河流居民形式的替代迁移模式有关。此外，有人建议在下游和上游同时存在本地和引入的 T. hakonensis 种群，而前者仅在上游栖息或占主导地位。