中国对虾线粒体16S rRNA基因序列分析

中国对虾(Fenneropenaeus chinensis)是我国海洋渔业重要的经济虾种之一。本研究以相应引物对野生群体和人工培育第1代、第4代、第5代、第6代群体(CP1、CP4、CP5、CP6)的各2个个体的线粒体16SrRNA基因片段进行了PCR扩增和序列测定分析。分析结果表明，测得的16SrRNA基因片段长为520bp，10个中国对虾个体间无碱基差异，其A、T、G、C含量分别为171bp(32．88％)、176bp(33．85％)、104bp(20．00％)、69bp(13．27％)，AT含量明显高于GC含量。利用其中长度为413bp的同源序列，以环斑鼓虾(Alpheus armillatus)为外群探讨了对虾科(Penaeidae)中的对虾属、美对虾属、明对虾属、囊对虾属和滨对虾属5个属(Penaeus，Farfantepenaeus,Fenneropenaeus,Marsupenaeus,Litopenaeus)12种对虾间的系统关系。以NJ法构建的分子系统树显示可将以上12种虾类分为两个大群：中国对虾和斑节对虾先聚到一起后与日本对虾聚成一大群；美对虾属、滨对虾属个体各聚成1支后聚成一大群，最后与中国对虾等聚到一起。同时可见，小褐美对虾(F．subtilis)与保罗美对虾(F.paulensis)、南方滨对虾(L.schmitti)与白滨对虾(L.setiferus)种间的亲缘关系较近。

Sequence analysis on mitochondrial 16S rRNA gene in Fenneropenaeus chinensis

Fenneropenaeus chinensis is of economical importance in marine fishery of China. This paper deals with the PCR amplification and sequence analysis of mitochondrial 16S rRNA gene fragment of its wild and cultured populations (CP1, CP4, CP5 and CP6). There was no difference among the F. chinensis individuals in the sequence of 520 bp obtained in this research. The A, T, G and C contents of the sequence were 171 bp (32.88%), 176 bp (33.85%), 104 bp (20.00%) and 69 bp (13.27%) respectively, and the content of AT was higher than that of GC. Furthermore, 413 bp of the fragment was used to discuss the phylogenetic relationship of 12 Penaeidae shrimps belonging to genera Penaeus, Farfantepenaeus, Fenneropenaeus, Marsupenaeus and Litopenaeus using Alpheus armillatus as the outgroup. The molecular phylogenetic tree constructed by neighbor-joining method showed that there were two large shrimp clusters. F. chinensis and P. monodon were clustered first, and then clustered with M. japonicus; another large shrimp cluster was Farfantepenaeus cluster with Litopenaeus cluster consisting of their individuals. The results also indicated that there was a closer genetic relationship between genus Farfantepenaeus and genus Litopenaeus; also between F. subtilis and F. paulensis, L. schmitti and L. setiferus.