Genetic diversity and temporal changes of an endemic cyprinid fish species, Ancherythroculter nigrocauda, from the upper reaches of Yangtze River.

Dong-Dong Zhai,Wen-Xuan Cao,Huan-Zhang Liu,Wen-Jing Li,Xin Gao

doi:10.24272/j.issn.2095-8137.2019.027

Abstract

Small populations with low genetic diversity are prone to extinction. Knowledge on the genetic diversity and structure of small populations and their genetic response to anthropogenic effects are of critical importance for conservation management. In this study, samples of Ancherythroculter nigrocauda, an endemic cyprinid fish from the upper reaches of Yangtze River, were collected from five sites to analyze their genetic diversity and population structure using mitochondrial cytochrome b gene and 14 microsatellite loci. Haplotype diversity, nucleotide diversity, and expected heterozygosity indicated that the A. nigrocauda populations had low genetic diversity, and decreased heavily from 2001 to 2016. Significant genetic differentiation was found among different populations in the cyt b gene and SSR markers based on the genetic differentiation index (F ST), whereas no differentiation was found in 2001. Haplotype genealogy showed that eight out of 15 haplotypes were private to one population. The SSR STRUCTURE analysis showed that there were four genetic clusters in the A. nigrocauda samples, with each population forming a single cluster, except for the Chishui River (CSR) and Mudong River (MDR) populations, which formed a common cluster. Therefore, loss of genetic diversity and increased genetic differentiation were found in the A. nigrocauda populations, which could be attributed to dam construction, overfishing, and water pollution in the upper Yangtze River. It is therefore recommended that the government should ban fishing, control water pollution, increase river connectivity, and establish artificial breeding and stocking.

Highlights

Genetic diversity of a species determines its adaptive capacity and evolutionary potential (Altizer et al, 2003; Pinsky & Palumbi, 2014)
An understanding of the genetic variability and structure of small populations and their genetic responses to anthropogenic effects is of critical importance for conservation management (Keyghobadi, 2007; Zhang et al, 2007) and for formulating the appropriate scales and subunits (Moritz, 1999) for sustainable long-term conservation
Cyt b gene marker Genetic diversity and demographic history Following alignment, a 1 140 bp cyt b gene sequence was obtained for 239 individuals

Summary

Introduction

Genetic diversity of a species determines its adaptive capacity and evolutionary potential (Altizer et al, 2003; Pinsky & Palumbi, 2014). Adverse anthropogenic influences can accelerate loss of genetic diversity within populations and differentiation among. Genetic impoverishment can accelerate the process of local extinction of small populations (Hedrick & Kalinowski, 2000). The Yangtze River supports 378 fish species, of which 162 are endemic (Yu et al, 2005), representing the highest fish diversity in the Palearctic region (Matthews, 1998). The upper Yangtze River refers to the reach above Yichang City and reportedly contains 124 endemic fish species (Cao, 2011). The upper Yangtze River is a crucial area for the conservation of fish diversity and genetic resources. Due to dam construction, overfishing, and water pollution, fish diversity in this region has decreased sharply and many species have become endangered (Fu et al, 2003; Park et al, 2003; Zhong & Power, 1996)

Objectives

Methods

Results

Conclusion