噬菌体及其宿主终端酶序列的系统进化研究  

Phylogenetic analysis of terminase sequences-evidence for horizontal gene transfer between phages and their bacterial hosts during evolution

作　　者：沙诗宇[1] 张玮玮[2] 马飞[1] 

机构地区：[1]辽宁师范大学海洋生物功能基因与蛋白质组学研究所,大连116029 [2]山西生物应用职业技术学院,太原030031

出　　处：《安徽农业大学学报》2009年第1期39-43,共5页Journal of Anhui Agricultural University

基　　金：国家自然科学基金(60575005);863计划项目(2007AA09Z428);教育部科学技术重点项目(206032);大连市科技计划项目(2006E11SF068)共同资助

摘　　要：在原核生物的进化过程中,基因的横向转移(HGT)是一个重要的进化机制。为了研究HGT在噬菌体及其宿主体内的发生情况,分析多个物种的终端酶蛋白质序列。结果显示,大部分噬菌体与其宿主间的蛋白质序列中,终端酶的大、小亚基的同源性都非常之高,小亚基的序列几乎与其宿主完全一致。相比之下,噬菌体间的蛋白质序列同源性非常低。系统发生分析显示,序列相似性高的噬菌体较容易与其宿主聚集,产生寄生关系。结果表明,在噬菌体及其选择的宿主之间存在HGT,而且这种作用可能对终端酶的进化产生重要的影响。Horizontal gene transfer （HGT） is an important evolutionary mechanism in prokaryotic genome evolution and has been widely studied. To investigate the occurrence of HGT in phages and their bacterial hosts, we have analyzed protein sequences of terminase across different species. Our results demonstrated that, in most phages, protein sequences of both small and large terminase subunits （small subunits in particular） are almost identical to those of their hosts, while sequences from various phages have much lower identity in between. Phylogenetic analysis also suggests that some phages seem to converge with their hosts rather than other phages. These strongly suggest that HGT probably exists between the selected phages and their bacterial hosts, which may have played an important role in terminase evolution.

关 键 词：细菌 噬菌体 基因横向转移 分子进化 终端酶 

分 类 号：Q936[生物学—微生物学] Q7