Expansion and contraction of lake basin shape the genetic structure of Sinocyclocheilus (Osteichthyes: Cypriniformes: Cyprinidae) populations in Central Yunnan, China

Geological events can strongly affect the genetic structures and differentiation of fish populations. Especially, as an endemic fish of the genus Sinocyclocheilus in the Yunnan‐Guizhou Plateau, the effects of key geological events on the distributions and genetic structures remain poorly understood. Examining the phylogeographic patterns of Sinocyclocheilus fishes can be useful for elucidating the spatio‐temporal dynamics of their population size, dispersal history and extent of geographical isolation, thereby providing a theoretical basis for their protection. Here, we used single nucleotide polymorphisms (SNP) method to investigate the phylogeographic patterns of Sinocyclocheilus fishes. Our analysis supports the endemicity of Sinocyclocheilus, but the samples of different regions of Sinocyclocheilus contain multiple ancestral components, which displayed more admixed and diversified genetic components, this may be due to the polymorphism of the ancestors themselves, or gene infiltration caused by hybridization between adjacent species of Sinocyclocheilus. We estimate that the most recent common ancestor (MRCA) of Sinocyclocheilus fish in the Central Yunnan Basin at approximately 3.75~3.11 Ma, and infer that the evolution of Sinocyclocheilus in the central Yunnan Basin is closely related to the formation of plateau lakes (around 4.0~0.02 Ma), and identifies the formation of Dianchi Lake and Fuxian Lake as key geological events shaping Sinocyclocheilus population structure. It is also the first time to prove that the altitude change has a great influence on the genetic variation among the populations of Sinocyclocheilus. Expansion and contraction of lake basin shape the genetic structure of Sinocyclocheilus (Osteichthyes: Cypriniformes: Cyprinidae) populations in central Yunnan, China; 2. The geographical isolation and the unique ecological preferences of Sinocyclocheilus fishes were key factors driving population differentiation