非洲兽总目核糖核酸酶基因超家族的分子进化研究

Molecular Evolution of the RNASE A in Afrotheria

【目的】追溯和揭示非洲兽总目核糖核酸酶基因超家族(RNASE A)的分子进化。【方法】以Blastn与tBlastn方法分析鉴定7个非洲兽总目物种RNASE A成员;利用ClustalX和MEGA 7.0软件比对翻译RNASE A功能基因的氨基酸序列;基于http://isoelectric.ovh.org在线预测功能基因等电点;利用MrBayes v3.1.2.构建BI系统发育树。【结果】分析鉴定获得82条RNASE A序列,包含64条功能基因和18条假基因;RNASE A序列长度377～654 bp,典型RNASE A序列特征在RNase1～8中相对保守,而在非典型的成员RNase9～13变异位点多;各物种基因的等电点在5.03～9.17之间;长鼻目大象(Loxodonta africana) RNase1、RNase6和管齿目土豚(Orycteropus afer) RNase4发生基因复制,大象RNase1经历了"生与灭"的进化模式。【结论】首次深入开展非洲兽总目RNASE A分子进化研究,增加对该基因超家族的认识,为后续研究奠定了基础。

[Purposes]To trace and demonstrate the molecular evolution of RNASE A in Afrotheria.[Methods]RNASE A sequences were identified in 7 Afrotheria species using Blastn and tBlastn methods,then functional sequences were translated to proteins by ClustalX and MEGA 7.We predicted the isoelectric point(pI)of each protein on the web(http://isoelectric.ovh.org).Phylogenetic tree was reconstructed using MrBayes v3.1.2.[Result]We obtained 82 RNASE A sequences that include 64 functional genes and 18 pseudogenes.These sequences range from 377 to 654 bp in length.The trait of RNASE A is relative conserved in RNase1-8,whereas it is variable in the non-typical RNASE A members(RNase9-13).The isoelectric points range from 5.03 to 9.17.Gene duplications of RNase1,RNase6 and RNase4 were identified in the Loxodonta africana and Orycteropus afer,respectively.The evolution pattern of the“birth and death”was identified in L.africana.[Conclusions]We firstly denomstrated the molecular evolution of the Afrotheria RNASE A,increasing the understanding of the RNASE A and established foundation for the future studies.