三疣梭子蟹4个野生群体线粒体16S rRNA和COⅠ基因片段的比较分析

Sequence Analysis of Mitochondrial 16S rRNA and COⅠ Gene Fragments of Four Wild Populations of Portunus trituberculatus

对分别采自辽东湾、莱州湾、海州湾和舟山的三疣梭子蟹(Portunus trituberculatus)4个野生群体的线粒体16SrRNA和COⅠ基因片段进行了扩增和测序,分别得到长度为524 bp和658 bp的片段。2段序列的碱基组成均显示较高的A+T比例(16S rRNA基因70.8%,COⅠ基因63%),这与果蝇、虾类、蟹类等无脊椎动物的16S rRNA和COⅠ基因片段研究结果相似。通过对三疣梭子蟹16S rRNA和COⅠ基因片段遗传特征的研究,发现种内变异较低,在16个样本中,16S rRNA基因序列中共检测到1个变异位点,2种单倍型;COⅠ基因序列中共检测到4个变异位点,5种单倍型。另外,以中华绒螯蟹为外群探讨了梭子蟹科(Portunidea)几个属种的系统进化关系。用MEGA4.0软件中的NJ法构建了系统进化树,基于16S rRNA和COⅠ2种片段的聚类结果均显示梭子蟹属(Portunus)与美青蟹属(Callinectes)亲缘关系最近,先聚在一起,然后再与蟳属(Charybdis)聚在一起,最后才与外群中华绒螯蟹聚在一起,这一结果与传统分类基本一致。

Mitochondrial 16S rRNA gene and COⅠ gene fragments were amplified and sequenced from 4 wild populations of Portunus trituberculatus.Respectively,524 bp and 658 bp long partial gene fragments of the 16S rRNA gene and the COⅠ gene were obtained.A high percentage of A＋T base composition in the two sequences was observed,which was similar to the results of studies on drosophila,shrimp,crab and other invertebrates.Little sequence variation was observed in 16S rRNA gene and COⅠ gene fragments within species.Two haplotypes were identified from 16 samples with 1 variation site of 16S rRNA gene and 5 haplotypes were identified from 16 samples with 4 variation sites of COⅠ gene.In addition,the phylogenetic relationship among several genera of Portunidea was discussed using Eriochier sinensis as the out-group.The molecular phylogenetic trees were constructed by the NJ method using software MEGA4.0,and Portunus was clustered with Callinectes first,then they were clustered with Charybdis,and finally with Eriochier sinensis.The results are consistent with classical taxonomy.