南方拟微卫星标记筛选及遗传多样性分析

Microsatellite Screening and Genetic Diversity Analysis of Gudgeon Pseudohemiculter dispar in Pearl River Basin

南方拟■是一种分布于长江以南各水系的小型经济鱼类,目前仅有野生资源。为查明珠江流域其群体遗传结构现状,试验采用RAD-Seq技术筛选出36个多态性微卫星标记,其中29个为高度多态性(多态信息含量>0.50)位点,6个为中度多态性(0.25<多态信息含量<0.50)位点和1个为低度多态性(多态信息含量<0.25)位点。选取6个高度多态性位点研究珠江流域的北江、桂江、都柳江、融江、左江、右江、黔江及郁江8个江段南方拟■群体的遗传多样性和种群分化情况,结果显示,共检测到98.17个等位基因,平均等位基因数、有效等位基因数、观测杂合度、期望杂合度、香农指数和多态信息含量值分别12.2713、6.0575、0.5389、0.7679、1.8974和0.7379,表明珠江流域南方拟■的遗传多样性丰富。6个微卫星位点在8个群体中检测结果显示,平均群体间分化系数为0.1028,表明10.28%的遗传变异来自于群体间,89.72%的遗传变异来自于群体内,属于中等分化水平;平均群体内近交系数为0.2987,表明群体内杂合子缺失严重;基因流为1.0075~4.7308,说明群体间的基因流足以抵制遗传漂变。本研究的结果可为南方拟■种质资源保护和开发利用提供科学依据。

Thirty-six polymorphic microsatellite markers were screened in gudgeon Pseudohemiculter dispar (Peters 1880), a small economical wild fish distributed in various freshwater drainages of south Yangtze River, by RAD-Seq technology, including 29 high polymorphism (polymorphic information content, PIC>0.50), 6 moderate polymorphism (0.25<PIC<0.50), and 1 low polymorphism (PIC<0.25). Six highly polymorphic microsatellite loci were used to analyze the genetic diversity and genetic differentiation of 8 populations of gudgeon in Pearl River basin including Beijiang, Guijiang, Duliujiang, Rongjiang, Zuojiang, Youjiang, Qianjiang and Yujiang, with alleles of 98.17, observing allele number of 12.2713, effective allele number of 6.0575, observed heterozygosity of 0.5389, expected heterozygosity of 0.7679 , Shannon′s Information Index of 1.8974 and PIC of 0.7379, indicating that there was high level of genetic diversity among 8 populations of gudgeon in Peal River basin. The analysis of molecular variance showed that average populations differentiation (Fst) was 0.1028 and the inbreeding coefficient (Fis) was 0.2987, which implied that 10.28% genetic variation was between populations and 89.72% variation within population, showing the moderate level of genetic differentiation. The gene flow varying from 1.0075 to 4.7308 suggested that 8 populations be stable enough to resist genetic drift. The findings provided scientific basis for genetic resource preservation and management in gudgeon.