Abstract:

Aim: Culter recurviceps (Cypriniformes: Cyprinidae) is an economic fish species in South China. Nevertheless, the resources of this species declined rapidly during recent years due to water conservancy, overfishing, and environmental pollution. Therefore, more attention and conservation measure are needed for this species. Population genetic analyses can both reveal genetic diversity and population structure of particular species and provide implications for management and conservation of these species. The aim of this study is to investigate the population genetic structure and genetic diversity of C. recurviceps and further provide implications for the preservation and reasonable development of its resources.
Methods: We collected 207 individuals from 23 populations in the drainages in Southern China. With respect to the 207 individuals, two mitochondrial genes (Cytb and ND2) were sequenced and the corresponding mitochondrial COI gene was obtained from the Barcode of Life Data System (BOLD) database. We then combined the three genes to study the genetic structure and genetic diversity of C. recurviceps populations. Multiple analyses including phylogenetic analysis, divergence time estimates, haplotype network, population genetic analyses, and Mantel tests were employed.
Results: Phylogenetic analysis and haplotype network revealed that C. recurviceps populations contained three lineages (I, II and III). The members of lineages I and III contained populations from the Pearl River and the representatives of lineage II comprised of populations from the Hainan Island. Divergence time estimates indicated the three lineages were split between 0.028 and 0.251 million years ago (Ma), suggesting that Pleistocene climate change may have triggered the divergence of the three lineages. Population genetic analyses showed significant genetic differentiation (F_ST = 0.511, P < 0.001) and isolation by distance pattern (R = 0.348, P = 0.0010) was observed among C. recurviceps populations. Demographic analyses revealed that C. recurviceps populations might experience population expansion during 0.010-0.025 Ma, implying that Pleistocene climatic fluctuations have influenced the population size and distribution of C.recurviceps populations.
Conclusion: We observed that C. recurviceps populations in South China consisted of three mitochondrial lineages. Pleistocene climate changes have not only triggered the divergences of the three lineages, but also influenced the demographic history of C. recurviceps populations. Furthermore, spatial distance acted as a key factor that improved the population differentiation among C. recurviceps populations.

Key words: Culter recurviceps, population structure, genetic diversity, multi-loci