| 长江上游长鳍吻鮈群体线粒体控制区遗传多样性分析 |
| Genetic Structure and Diversity of Rhinogobio ventralis in the Upper Yangtze River Obtained by Analysis of the Mitochondrial DNA Control Region |
| 投稿时间：2016-12-29 修订日期：2017-09-19 |
| DOI：10.15928/j.1674-3075.2018.01.012 |
| 中文关键词:长鳍吻鮈 线粒体 遗传多样性 长江上游 |
| 英文关键词:Rhinogobio ventralis mitochondrial DNA genetic diversity upper reaches of the Yangtze River |
| 基金项目:国家自然科学基青年项目（51309167）；中国长江三峡集团公司项目（0799570）；国家自然科学基金项目（51509169；51379134）。 |
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| 中文摘要: |
| 分析长鳍吻鮈群体遗传结构和遗传多样性，为研究过度捕捞、水电开发等人类活动对长鳍吻鮈的长期生态学效应及其物种适应机制提供基础数据，同时也为该物种保护策略的制定和调整提供科学数据支持。2014和2015年，于长江上游干流江津、宜宾、皎平渡和格里坪采集长鳍吻鮈，利用线粒体控制区序列的特异性引物，通过PCR扩增以及序列测定，获得125份长鳍吻鮈线粒体控制区序列。结果表明：125尾长鳍吻鮈样品共检测到多态位点25个，单倍型30种，平均单倍型多样性指数（Hd）和核苷酸多样性指数（Pi）分别为0.785和0.00140；中性检验（Tajima's D为-1.97524, P<0.05；Fu's Fs为-31.374, P=0.000)和序列错配分布结果表明，长江上游长鳍吻鮈历史上经历过“遗传瓶颈”和种群扩张；分子方差分析(AMOVA)结果表明，群体间的遗传变异绝大部分来源于群体内部（99.07%），群体间无显著遗传分化(FST =0.00933,P>0.05)；单倍型网络、Kinura 2?Parameter遗传距离和平均基因流均显示，4个长鳍吻鮈群体间存在广泛的基因交流，群体间无遗传分化。各群体间没有显著遗传分化，基因交流频繁，可将长江上游长鳍吻鮈作为单一的进化显著单元（ESU）进行管理。 |
| 英文摘要: |
| Rhinogobio ventralis (Teleostei, Cyprinidae, Gobioninae) is an important commercial fish endemic to the upper Yangtze River and its tributaries. Once widely distributed, wild populations have declined dramatically in recent years and face extinction as a result of water pollution, overfishing and cascade hydropower development. Habitat fragmentation caused by damming has disrupted gene exchange among populations and affected genetic structure and diversity. Understanding the genetic structure of remaining populations would support management decision making and adjustment of protection measures developed to conserve and restore wild R. ventralis populations. Evaluation of genetic diversity and differentiation among wild populations would also benefit the artificial propagation program for this species. Mitochondrial DNA (mtDNA) is inherited maternally and the effective population size for mtDNA is one-fourth that of nuclear genes and is a suitable genetic marker for endangered fish species. In the present work, sequencing of the mitochondrial DNA control region (D-loop) was carried out to assess the genetic divergence and population structure of natural R. ventralis populations from four sections of the upper Yangtze River： Jiangjin, Yibin, Jiaopingdu and Geliping. In 2014 and 2015, R. ventralis sampling was carried out in the four sections and a total of 125 R. ventralis specimens were collected： 28, 32, 23 and 42, respectively, from the Jiangjin, Yibin, Jiaopingdu and Geliping sections. The mitochondrial DNA control region sequence was obtained for each specimen using PCR amplification. The length of D-loop region of R. ventralis was approximate 1064 bp and the mean base composition (%) was as follows: A, 32.9; T, 31.5; G 21.6; C, 14.0. A total of 25 polymorphic sites and 30 different haplotypes were identified among the 125 specimens, with an average haplotype diversity index (Hd) of 0.785 and nucleotide diversity index (Pi) of 0.00140. Significant values of Tajima's D (-1.97524, P<0.05) and Fu's Fs (-31.374, P=0.000), together with a uni-modal mismatch distribution, revealed that a recent genetic bottleneck, or population expansion, occurred in R. ventralis. Molecular variance analysis (AMOVA) indicated that most of the genetic variation occurred within groups (99.07%), with no significant differences among groups (FST=0.00933, P>0.05). The haplotype network, Kinura 2-parameter distances and Nm value also indicated extensive gene exchange among the four wild R. ventralis populations, resulting in little or no genetic differentiation. In conclusion, these populations of R. ventralis in the upper Yangtze River should be considered as a single management unit with no significant genetic differentiation and frequent gene exchange between the different geographic groups. |
| 邵科,闫书祥,李伟涛,熊美华,唐会元,史方.2018.长江上游长鳍吻鮈群体线粒体控制区遗传多样性分析[J].水生态学杂志,39(1):76-82. |
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