Dong Weiwei, Wang Dengqiang, Tian Huiwu, Pu Yan, Yu Lixiong, Duan Xinbin, Liu Shaoping, Chen Daqing
Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China.
Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Wuhan, China.
PeerJ. 2019 Aug 6;7:e7393. doi: 10.7717/peerj.7393. eCollection 2019.
and are the only two species within the genus (Cyprinidae, Cypriniformes), and both are endemic to the upper reaches of the Yangtze River. In recent years, due to human activities, the natural resources available to both species have declined sharply. Sympatric species with overlapping niches inevitably compete for their habitats, and genetic structure and diversity can reflect population history and their potential for adaptation to changing environments, which is useful for management decisions.
In the present study, microsatellite DNA and mitochondrial DNA (mtDNA) markers were used to investigate the patterns of population genetic structure for and . Microsatellite DNA data, jointly with traditional summary statistics including and , were used to assess the population genetic structure by structure analysis. The mtDNA sequences were then used to examine these patterns through time to detect demographic history.
and exhibited high levels of genetic diversity in Yangtze River populations, except for two populations of in the Jinsha River, which were low in mtDNA diversity. showed genetic homogeneity among populations, whereas appeared to have significant geographic genetic divergence. Both species experienced a late-Pleistocene sudden population expansion in Yangtze River populations, but not in the Jinsha River populations of .
The genetic homogeneity of populations might result from similar population expansion events and environment features. The geographic genetic subdivision for between the Jinsha and Yangtze Rivers might be caused by the geographic isolation in the middle Pliocene, as well as climate and environmental heterogeneity.
和 是 属（鲤科，鲤形目）仅有的两个物种，二者均为长江上游特有物种。近年来，由于人类活动，这两个物种可利用的自然资源急剧减少。生态位重叠的同域物种不可避免地会争夺栖息地，而遗传结构和多样性能够反映种群历史及其适应环境变化的潜力，这对管理决策很有帮助。
在本研究中，利用微卫星DNA和线粒体DNA（mtDNA）标记来研究 和 的种群遗传结构模式。微卫星DNA数据与包括 和 在内的传统汇总统计数据相结合，通过结构分析来评估种群遗传结构。然后利用mtDNA序列来研究这些模式随时间的变化，以检测种群历史。
长江种群中的 和 表现出较高水平的遗传多样性，但金沙江的两个 种群的mtDNA多样性较低。 种群间表现出遗传同质性，而 似乎存在显著的地理遗传分化。两个物种在长江种群中都经历了更新世晚期的种群突然扩张，但金沙江的 种群没有。
种群的遗传同质性可能源于相似的种群扩张事件和环境特征。金沙江和长江之间的 地理遗传细分可能是由上新世中期的地理隔离以及气候和环境异质性造成的。
