| 摘要: |
| 使用mtDNA作为分子标记，基于1022 bp和1322 bp左右的部分序列分析刀鲚(Coilia nasus)、湖鲚(C. nasus taihuensis)、七丝鲚(C. grayii)及凤鲚(C. mystus)成鱼之间的遗传关系。结果显示，刀鲚和湖鲚间的遗传距离分别为0.0036±0.0008和0.0038±0.0008，凤鲚与刀鲚、湖鲚的遗传距离分别为0.1215±0.0111、0.1228±0.0111(Cyt b)和0.1075±0.0108、0.1067±0.0107 (D-loop)，七丝鲚与刀鲚、湖鲚的遗传距离分别为0.0342±0.0056、0.0351±0.0057 (Cyt b)和0.0527±0.0069、0.0529±0.0070 (D-loop)，七丝鲚和凤鲚间的遗传距离分别为0.1158±0.0111和0.1123±0.0111。用Kimura双参数模型构建的2种序列的NJ分子系统树均显示，湖鲚和刀鲚不能形成独立的分支，而是混合聚在一起形成1个分支；七丝鲚和凤鲚则形成另外2个分支。首先根据采样点不同可初步断定未知仔幼鱼为刀鲚，稚鱼为湖鲚，而后对未知种仔幼鱼、稚鱼和刀、凤鲚鱼卵的2种序列的分析发现，不同采集点内部的这些早期生活个体间的遗传距离分别为0.0024~0.0032和0.0025~0.0082。在Kimura双参数模型构建的NJ分子系统树中，未知种仔幼鱼、稚鱼、刀鲚鱼卵与刀鲚、湖鲚聚为一类，凤鲚鱼卵与凤鲚聚为一支。由此可见，Cyt b基因序列和D-loop序列作为分子标记，虽然可以区分刀鲚、凤鲚以及七丝鲚的仔幼、稚鱼及鱼卵，但不能有效区分湖鲚和刀鲚的早期生活个体。 |
| 关键词: 鲚属 早期生活史 Cyt b基因 D-loop序列 |
| DOI： |
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| Comparison of D-loop and Cytochrome b Sequences Among Different Coilia Species and Their Potential Use in Analysis for the Identification of Species at Early Life Stages |
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SUN Chao1, LIU Hongbo2,3, JIANG Tao2,3, XUAN Zhongya1, YANG Jian1,2,3
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1.Fisheries College, Nanjing Agricultural University, Wuxi 214081;2.Key Laboratory of Fishery Ecological Environment Assessment and Resource Conservation in Middle and Lower Reaches of the Yangtze River, Chinese Academy of Fishery Sciences;3.Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081
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| Abstract: |
| Based on 1022 bp and 1322 bp sequences, partial nucleotide sequences of Cyt b and D-loop segments of mtDNA were analyzed for Coilia nasus, C. nasus taihuensis, C. grayii, and C. mystus to develop a reference dataset for species identification in the genus Coilia. The genetic distances were 0.00360±0.00083 and 0.00378±0.00082 between C. nasus and C. nasus taihuensis, 0.12146±0.01106 and 0.10753±0.01076 between C. mystus and C. nasus, 0.12207±0.01111 and 0.10674±0.01074 between C. mystus and C. nasus taihuensis, 0.03418±0.00561 and 0.05267±0.00686 between C. nasus and C. grayii, 0.03506±0.00568 and 0.05287±0.00698 between C. nasus taihuensis and C. grayii, as well as 0.11585± 0.01109 and 0.11233±0.01114 between C. grayii and C. mystus, respectively. Based on the sequences of the Cyt b gene and D-loop and the neighbor-joining (NJ) molecular dendrogram using Kimura 2-parameters, individuals of C. nasus and C. nasus taihuensis were combined in a cluster while C mystus and C. grayii formed another two clusters. First, based on sampling sites, the identities of the unknown larvae from the estuary of the Yangtze River and unknown juveniles from the Taihu Lake could be deduced preliminarily as C. nasus and C. nasus taihuensis, respectively. Then, nucleotide sequences of Cyt b and D-loop of larvae and eggs of genus Coilia were analyzed and compared with the reference established above. Genetic distance ranged from 0.0024 to 0.0032 and 0.0025 to 0.0082, respectively, within the larva and egg individuals collected from different places. The NJ molecular dendrogram showed that all the unknown larvae, the eggs of C. nasus, adult C. nasus, and C. nasus taihuensis clustered together. In contrast, individual eggs of C. mystus and adult C. mystus formed a separate cluster. Thus, Cyt b and D-loop sequence analysis could be used to identify unknown Coilia nasus, C. grayii, and C. mystus at early life stages, but could not effectively be used to identify unknown individuals at early life stages between C. nasus and C. nasus taihuensis. |
| Key words: Genus Coilia Early life stage Cyt b gene sequence D-loop sequence |
