多刺蚁属线粒体细胞色素b序列变异及系统发育关系分析

Sequence Variation and Phylogenetic Relationship of Mitochondrial Cytochrome b from Polyrhachis

多刺蚁属18种昆虫线粒体细胞色素b基因都显示出高A+T含量,达到65.11%~73.66%,表现出很强的A/T碱基偏好性。针对748 bp的基因核苷酸多序列比对显示细胞色素b基因之间同源性高,碱基之间无插入或缺失突变,序列变异形式主要表现为替换。对细胞色素b蛋白的部分序列(133~143个氨基酸)进行比对,结果显示完全无变异的氨基酸有34个,占总氨基酸数目的 23.78%~25.56%,同时也鉴定出至少6个保守的功能结构域。基于细胞色素b蛋白部分序列采用邻接法构建了多刺蚁属分子系统树,其中4对蚁种亲缘关系较近,有3个蚁种在进化树中各自形成一个独立的分支,显示出不同的进化起源。

Mitochondrial cytochrome b genes from 18 Polyrhachis species show high A+T content,being as high as 65.11%~73.66%. They show a strong A+T bias. Multiple sequence alignment of 748 bp partial nucleotide acid sequences of cytochrome b genes of Polyrhachis species showed that there is a high homology between cytochrome b genes,and there is no any insertion or deletion mutation among bases. The main form of sequence variation was showed to be substitution. Alignment of partial sequences(133~143 amino acids) of cytochrome b proteins showed that there are 34 amino acids with no any variation,which account for 23.78% ~25.56% of total amino acids.Meanwhile,at least six conserved functional domains were also identified. Based on the partial sequences of cytochrome b proteins,we constructed a phylogenetic tree using Neighbor-joining method. In this phylogenetic tree,four pairs of ant species have a close genetic relationship and three ant species form an independent clade,showing a different evolutionary origin.