文章摘要
基于线粒体Cyt-b序列的太湖湖鲚与短颌鲚种群遗传分析
Analysis of population genetic divergence of Coilia nasus taihuensis and Coilia brachygnathus based on mitochondrial Cyt b gene
投稿时间:2019-04-19  修订日期:2019-05-09
DOI:
中文关键词: 湖鲚  短颌鲚  细胞色素b  遗传分化
英文关键词: Coilia nasus taihuensis  Coilia brachygnathus  Cyt-b  genetic divergence
基金项目:
作者单位E-mail
轩中亚 南京农业大学无锡渔业学院 963531709@qq.com 
姜 涛 中国水产科学研究院淡水渔业研究中心  
刘洪波 中国水产科学研究院淡水渔业研究中心  
陈修报 中国水产科学研究院淡水渔业研究中心  
杨 健 中国水产科学研究院淡水渔业研究中心 jiany@ffrc.cn 
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中文摘要:
      为了解太湖内的湖鲚与短颌鲚的遗传多样性,遗传分化及种群历史动态情况,利用线粒体细胞色素b(Cyt-b)基因,开展了种群遗传学研究。结果显示:47条序列共有变异位点26个,其中简约信息位点12个,共得到22个单倍型。两物种间Fst值达0.703,分化程度较高,种群间的基因流仅为0.212,湖鲚种群内平均Kimura双参数遗传距离为0.002,短颌鲚种群内为0.001,而湖鲚与短颌鲚种间平均Kimura双参数遗传距离为0.005,高于湖鲚及短颌鲚各自种群内部。系统发育树和单倍型网络图结果显示湖鲚与短颌鲚分成两个大的类群,存在一个湖鲚个体与短颌鲚具有共有单倍型,总体结果显示湖鲚与短颌鲚之间存在明显的遗传分化, Cyt-b序列可以用于区分湖鲚与短颌鲚个体。
英文摘要:
      Coilia nasus taihuensis has become an absolute dominant species of fish in the Taihu Lake. However, problem is still available for confusion between the fish of C. nasus taihuensis and C. brachygnathus. In the lake, actually, the fish with maxillary length longer than head length are believed as the former, but the fish with maxillary length less than head length are believed as the latter. As previous studies classified the all the Coilia fish in the Taihu Lake as C. nasus taihuensis, it makes doubts about the correctness of the results of the study on genetic differentiation between C. nasus taihuensis and C. brachygnathus. Therefore, we first used morphological features to distinguish C. nasus taihuensis and C. brachygnathus, and then we determine genetic divergence among the two putative species, and to test if the Cyt-b sequence can identify unknown individuals at early life stages between C. brachygnathus and C. nasus taihuensis. In the present study we determined genetic diversity, genetic structure, genetic divergence, and population demographic history between the two phenotypes of Coilia nasus taihuensis and C. brachygnathus by means of mitochondrial Cyt b gene. A total of 22 haplotypes were found among 47 sequences of Cyt b gene from the 33 individuals of C. nasus taihuensis and 14 individuals of C. brachygnathus. The results showed that 26 polymorphic nucleotide sites were detected among all the Cyt b sequences including 12 parsimony-informative sites. The value of Kimura’s two-parameter distance within C. nasus taihuensis and C. brachygnathus were 0.002 and 0.001, respectively. Moreover, the value of Kimura’s two-parameter distance among C. nasus taihuensis and C. brachygnathus was 0.005. This situation meant that the genetic divergence among the two putative species was higher than that within their species. Fst analysis showed a significantly high level of genetic variance among the two putative species (Fst=0.703 P<0.001). Gene flow between the two putative species was 0.212, lower than 1, suggesting that the two phenotypes almost had no gene exchange. Additionally two distinct clades were detected by phylogenetic analysis, and they were for C. nasus taihuensis and C. brachygnathus, respectively. A haplotype was shared by the phenotypes. Furthermore, the median-joining network produced was similar to the topology of the phylogenetic tree. In summary, mtDNA analysis of this study revealed that there was significantly genetic divergence between C. nasus taihuensis and C. brachygnathus, the gene flow between them was weak, and, two distinct clades could be detected by phylogenetic analysis, and the Cyt-b sequence could be used in identifying unknown individuals at early life stages between C. brachygnathus and C. nasus taihuensis.
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