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

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.