线粒体基因片段在梭子蟹系统发育及物种鉴定中的应用

The Applications of mitochondrial DNA in phylogeny reconstruction and species identification of portunid crab

测定三疣梭子蟹(Portunus trituberculatus)9个个体COI基因部分序列467 bp,7个个体16 S rRNA基因部分序列519 bp,同时测定样品蟹1个个体COI基因部分序列468 bp。结合GenBank中收集的梭子蟹科COI,16 S rRNA两个基因所有同源序列信息,使用Kimura双参数模型采用邻接法(NJ)、最大简约法(MP)构建梭子蟹科分子系统发育树;将样品蟹测得的COI基因序列和已知属的其他蟹同源序列(429 bp)进行比对分析。结果分析表明:两个基因片段序列平均碱基AT数量分数都明显高于GC数量分数;梭子蟹属与美青蟹属关系最近,属应为区别于梭子蟹属、美青蟹属、青蟹属的另一支,支持属应划分在短桨蟹亚科的观点;根据遗传距离以及转换/颠换(R)值分析,判定出样品为锐齿。本试验运用线粒体基因片段探讨了梭子蟹类的系统发育关系以及样品蟹的种类鉴定,为线粒体基因片段在梭子蟹的物种鉴定和系统发育重建中的开发和利用提供重要参考。

The partial sequences of COI and 16S genes were determined from Portunus trituberculatus, and partial sequences of COI was determined from sampled specimen. All homologous partial sequences of COI and 16S in Portunidae were collected from GenBank and aligned with the homologous sequences of P. trituberculatus. The NJ tree and MP tree were constructed using Kimura 2-parameter model. Homologous sequences （429 bp） of sampled specimen and genus Charybdis were aligned. The results show that the average content of AT is obviously higher than that of GC in both genes. Charybdis is a different group which separated from Portunus, Callinectes and Scylla. Charybdis should be included in subfamily Thalamitinae but not in subfamily Portuninae. Sampled specimen is identified as Charybdis acuta for its genetic distance and R value. This experiment researched on the phylogenetic relationships of portunid crab and identification of sampled specimen, and it provides important information for the phylogeny reconstruction and species identification of portunid crab.