西昌华吸鳅的微卫星引物筛选及赤水河四个地理种群的遗传多样性分析

采用高通量测序法对西昌华吸鳅(Sinogastromyzon sichangensis)基因组进行随机测序并筛选出符合条件的微卫星位点, 设计可用于PCR扩增的引物, 筛选出29对具有多态性的引物, 平均等位基因数为14.5, 观测杂合度(H_o)和期望杂合度(H_e)分别为0.620和0.882, 多态信息含量(PIC)为0.859。选取其中多态性较高的20对引物在赤水河及其支流的4个地理种群中进行扩增, 分析不同地理种群的遗传多样性和种群分化情况。结果表明, 赤水镇种群观测杂合度最高(0.669), 茅台镇种群观测杂合度最低(0.520); 习水河多态信息含量最高(0.868), 茅台镇种群多态信息含量最低(0.841)。赤水河干流的几个种群未出现显著分化, 而习水河种群与其他3个种群的遗传分化程度较高。AMOVA分析显示遗传变异主要发生在群体内, 群体间遗传变异仅占3.33%, 群体内遗传变异占96.67%。种群遗传结构分析表明, 赤水河干流整体遗传背景趋于一致, 而习水河种群则单独聚为一个亚类群。研究为西昌华吸鳅的资源保护和种群遗传学研究提供了基础资料。

ISOLATION OF MICROSATELLITE LOCI AND GENETIC DIVERSITY ANALYSIS OF SINOGASTROMYZON SICHANGENSIS

Sinogastromyzon sichangensis is a small-size fish endemic to the upper Yangtze River mainly distributed in main stream and tributaries. Twenty-nine polymorphic microsatellite loci of the S. sichangensis were isolated by next-generation sequencing techniques. Four wild populations in Chishui River were amplified by 20 loci with mean alleles 14.5. The mean observed (H_o) and expected (H_e) heterozygosity were 0.620 and 0.882, respectively and the mean polymorphic information content (PIC) was 0.859. The H_o ranged from 0.520 (Maotai Town) to 0.669 (Chishui Town) and PIC ranged from 0.841 (Maotai Town) to 0.868 (Xishui River). The F_st value and analysis of population structure revealed a genetic differentiation between populations from Xishui River and the main stream of Chishui River. AMOVA showed that the genetic variation was 3.33% among populations while it was 96.67% within populations. These novel loci could use to investigate the population genetics and biological resource conservation strategy in S. sichangensis.