脊椎动物Delta-Protocadherin亚家族的系统进化分析

An Analysis on the Subfamily Evolution of Vertebrate Delta-Protocadherin

为了研究脊椎动物δ-Pcdh亚家族的进化,本研究以11种脊椎动物的11个Pcdh基因为研究对象,进行了序列比对和系统发育关系重建,并利用PAML对δ2-Pcdh亚家族进行选择压力分析,同时对正选择位点进行了定位。研究发现,δ-Pcdh可以分为δ1-Pcdh(Pcdh1,Pcdh7,Pcdh9,Pcdh11和Pcdh20)和δ2-Pcdh(Pcdh8,Pcdh10,Pcdh12,Pcdh17,Pcdh18和Pcdh19)两个亚家族。其中,δ1-Pcdh亚家族中Pcdh20位于系统树的基部,Pcdh1与Pcdh7和Pcdh9与Pcdh11分别构成姐妹群;δ2-Pcdh亚家族分为两个分支,一支由Pcdh8、Pcdh12和Pcdh18构成,另一支由Pcdh10、Pcdh17和Pcdh19构成,其第一个分支的3个基因均检测到了不同程度的正选择。随后,分析了正选择位点所在的结构域,探讨了正选择位点与蛋白质功能的关系。该研究为深入了解脊椎动物δ-Pcdh亚家族的进化提供了重要参考。

In order to study the evolution of vertebrate δ-Pcdh subfamily, 11 Pcdh genes of 11 vertebrates were selected to accomplish sequence alignment and reconstruct the phylogenetic tree. Furthermore, selective pressure analysis was performed on δ2-Pcdh by using PAML software, and positive selection sites were located to specific domains. The results indicated that δ-Pcdh members could be divided into 51-Pcdh （Pcdhl, Pcdh7, Pcdh9, Pcdhl 1, and Pcdh20） and δ2-Pcdh （Pcdh8, Pcdh10, Pcdh12, Pcdhl7, Pcdhl8, and Pcdhl9）. In δ1-Pcdh subfamily, Pcdh20 located at the base of the phylogeny, and Pcdhl and Pcdh7, Pcdh9 and Pcdhl 1 respectively constituted sister group. δ2-Pcdh subfamily was divided into two branches, one included Pcdh8, Pcdhl2, and Pcdhl 8, and the other included Pcdhl0, Pcdhl7, and Pcdhl9. Interestingly, all the three genes of the first branch were detected positive selection at different levels. Subsequently, we analyzed the domains of positive selection sites and discussed the relationship between these sites and the protein function. This study provided valuable references for better understanding the evolution of vertebrate δ-Pcdh subfamily.