光间受体视黄类物质结合蛋白基因(IRBP)在棉鼠亚科物种中的序列变异及其系统发育意义

Interphotoreceptor Retinoid Binding Protein Gene (IRBP) Variation and its Phylogenetic Implications among Sigmodontinae

以光间受体视黄类物质结合蛋白基因(IRBP)为研究对象,从GenBank中下载了棉鼠亚科66个种的IRBP序列,分析IRBP的结构及其在棉鼠亚科的进化关系。G+C含量高于A+T,密码子第3位点的G+C含量高达61.2%,并且呈现出较低的核苷酸多样性(3.786%)。IRBP在棉鼠亚科没有经历正向达尔文选择。以IRBP构建的系统发育树和以往研究的结果总体上是一致的,但由于本文样本数量的增加,发现Oryzomyini还存在第3个分支,不同于以往研究只划分了2个分支。同时系统发育树的结构表明Ichthyomyini和Sigmodontini很可能不是两个独立的族。另外和前人以细胞色素b基因构建的系统发育树相比较,树的结构总体上也是一致的。这些都表明IRBP在棉鼠亚科中有较好的应用效果,但要更好地解决此亚科存在的系统发育问题,重点在于增加用于分析的物种数量。

Sixty-six interphotoreceptor retinoid binding protein gene（IRBP）sequences from 66 Sigmodontinae species were analyzed in order to investigate its structure and differentiation.The content of G＋C was higher than that of A＋T,and was 61.2% at the third position of codon.Nucleotide diversity was low（3.786%）among all 66 sequences.In addition,IRBP did not experience positive selection.The reconstructed phylogenetic tree of IRBP for all 66 species matched the results of previous studies.However,with more samples,we found that there were three evolutionary clades within Oryzomyini,while previous studies only found two.Furthermore,the phylogenetic trees indicated that Ichthyomyini and Sigmodontini were probably not two independent tribes.Additionally,our results were consistent with the previous cyt b phylogenetic tree.Our analyses suggest that the IRBP could be used as molecular marker in the phylogenetic study of Sigmodontinae,but more species should be used in the phylogenetic study of Sigmodontinae.