翼手目核糖核酸酶4基因（RNase4）的分子进化研究
发布时间：2018-09-19 18:17
【摘要】：核糖核酸酶基因(RNase A)超家族作为脊椎动物所特有的基因家族是分子进化研究的重要模型。该基因家族因频繁的基因复制和假基因化事件而在不同物种中存在不同的基因数量,从而产生了功能分化。2013年,Goo等对哺乳动物核糖核酸酶基因(RNase A)超家族各成员的分析中发现其中的RNase4基因在翼手目中的Yinpterochiroptera亚目代表物种--马来大狐蝠(Pteropus vampyrus)有一个功能基因,而在Yangochiroptera亚目代表物种--莹鼠耳蝠(Myotis lucifugus)中有12个基因,发生了基因复制现象。提示RNase4基因在翼手目中可能具有特殊的进化模式和功能分化。而RNase4基因在翼手目中的其他物种中是否发生了基因复制,发生复制的时间及驱动力等都需要增加翼手目更多代表物种进行深入研究。本研究收集了翼手目两个亚目(Yinpterochiroptera 和 Yangochiroptera)五个超科(菊头蝠超科,狐蝠科,蝙蝠超科,鞘尾蝠超科和兔唇蝠超科)的9科25属28个物种,进行RNase4基因的分子进化研究。研究结果发现RNase4基因在Yangochiroptera亚目蝙蝠超科的蝙蝠科物种中发生了基因复制,而在其他研究的物种中,除了Yinpterochiroptera亚目狐蝠科的中央狐蝠中只检测到一个假基因外,其余都只检测到一个功能基因。中央狐蝠RNase4假基因化表明该基因在该物种中可能不具功能。系统发育研究结果表明蝙蝠科首先在祖先枝经历了一次基因复制事件,然后经历了一次假基因化事件。蝙蝠科中的鼠耳蝠属发生了大量的基因复制,而且以基因的形式聚集成簇,经历了至少两次基因复制。分歧时间估算也表明该基因复制发生在物种形成之前。此外,蝙蝠科的黄蝠属中的基因复制则发生在物种形成之后,为非常近期的一次基因复制。选择分析中的“位点特异”模型(site-specific model)检测到14个正选择位点,其中位点76(Q76E)和98(Q98K)都位于活性位点附近,推测其可能会通过影响核糖核酸酶4酶活性及底物结合活性产生功能改变。此外,选择分析中的“枝-位点”(branch-site model)模型在蝙蝠科中发生基因复制的B基因簇祖先枝中检测到显著的正选择信号及两个正选择位点(58和73)。以上研究结果表明蝙蝠科RNase4在适应性选择作用的驱动力下发生基因复制,并有可能产生了功能分化。本研究通过对翼手目更多代表物种的RNase4基因分子进化分析,揭示了翼手目RNase4基因复杂的进化模式,为后续的RNase4基因的功能研究提供了重要的理论依据。
[Abstract]:Ribonuclease gene (RNase A) superfamily as a unique gene family in vertebrates is an important model of molecular evolution. The gene family has different numbers of genes in different species due to frequent gene replication and pseudogenization events. In 2013, (RNase A) superfamily members of mammalian ribonuclease genes revealed that the RNase4 gene had a functional gene in the Yinpterochiroptera suborder of the order pteryophora, a species called (Pteropus vampyrus). However, there are 12 genes in the (Myotis lucifugus) of Rhinolophus Yangochiroptera, which is a representative species of Rhinolophus. It is suggested that RNase4 gene may have a special evolutionary pattern and functional differentiation in pterygoptera. However, whether or not the RNase4 gene replicates in other species in the order Pteroptera, the time and driving force of the replication need to be further studied by increasing the number of representative species in the order Pteroptera. In this study, 28 species belonging to 25 genera, 9 families and 25 genera of two superfamilies (Yinpterochiroptera and Yangochiroptera) of the order Yinpterochiroptera and Yangochiroptera were collected to study the molecular evolution of RNase4 gene. The results showed that the RNase4 gene was duplicated in the Yangochiroptera subfamily bat superfamily, while in other species, only one pseudogenic gene was detected in the central foxbats of the Yinpterochiroptera subfamily. Only one functional gene was detected in the rest. The RNase4 pseudogenization of central fox bat suggests that the gene may not function in the species. Phylogenetic studies showed that the family of bat experienced a gene replication event first and then a pseudogenetic event in the ancestral branch. A large number of gene replicas have occurred in the genus Rhinolophus in the family bat, and they have been clustered into clusters in the form of genes, which have undergone at least two gene replications. Estimation of divergence time also indicates that the gene replication occurs before species formation. In addition, gene replication in the genus Rhinolophus occurs after species formation and is a very recent one. The "locus specific" model (site-specific model) detected 14 positive-selective sites, of which both loci 76 (Q76E) and 98 (Q98K) were located near the active sites. It was speculated that they might produce functional changes by affecting ribonuclease 4 activity and substrate binding activity. In addition, the "branchs-site" (branch-site model) model in the selection analysis detected significant positive selection signals and two positive selection sites (58 and 73) in the progenitor branches of the B gene cluster in bats. The above results suggest that RNase4 in the family Bataceae may produce gene replication and functional differentiation under the driving force of adaptive selection. By analyzing the molecular evolution of the RNase4 gene which represents more species of pteryoptera, this study reveals the complex evolution pattern of the RNase4 gene of pteroptera, and provides an important theoretical basis for the further study of the function of RNase4 gene.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q953
本文编号：2250939
[Abstract]:Ribonuclease gene (RNase A) superfamily as a unique gene family in vertebrates is an important model of molecular evolution. The gene family has different numbers of genes in different species due to frequent gene replication and pseudogenization events. In 2013, (RNase A) superfamily members of mammalian ribonuclease genes revealed that the RNase4 gene had a functional gene in the Yinpterochiroptera suborder of the order pteryophora, a species called (Pteropus vampyrus). However, there are 12 genes in the (Myotis lucifugus) of Rhinolophus Yangochiroptera, which is a representative species of Rhinolophus. It is suggested that RNase4 gene may have a special evolutionary pattern and functional differentiation in pterygoptera. However, whether or not the RNase4 gene replicates in other species in the order Pteroptera, the time and driving force of the replication need to be further studied by increasing the number of representative species in the order Pteroptera. In this study, 28 species belonging to 25 genera, 9 families and 25 genera of two superfamilies (Yinpterochiroptera and Yangochiroptera) of the order Yinpterochiroptera and Yangochiroptera were collected to study the molecular evolution of RNase4 gene. The results showed that the RNase4 gene was duplicated in the Yangochiroptera subfamily bat superfamily, while in other species, only one pseudogenic gene was detected in the central foxbats of the Yinpterochiroptera subfamily. Only one functional gene was detected in the rest. The RNase4 pseudogenization of central fox bat suggests that the gene may not function in the species. Phylogenetic studies showed that the family of bat experienced a gene replication event first and then a pseudogenetic event in the ancestral branch. A large number of gene replicas have occurred in the genus Rhinolophus in the family bat, and they have been clustered into clusters in the form of genes, which have undergone at least two gene replications. Estimation of divergence time also indicates that the gene replication occurs before species formation. In addition, gene replication in the genus Rhinolophus occurs after species formation and is a very recent one. The "locus specific" model (site-specific model) detected 14 positive-selective sites, of which both loci 76 (Q76E) and 98 (Q98K) were located near the active sites. It was speculated that they might produce functional changes by affecting ribonuclease 4 activity and substrate binding activity. In addition, the "branchs-site" (branch-site model) model in the selection analysis detected significant positive selection signals and two positive selection sites (58 and 73) in the progenitor branches of the B gene cluster in bats. The above results suggest that RNase4 in the family Bataceae may produce gene replication and functional differentiation under the driving force of adaptive selection. By analyzing the molecular evolution of the RNase4 gene which represents more species of pteryoptera, this study reveals the complex evolution pattern of the RNase4 gene of pteroptera, and provides an important theoretical basis for the further study of the function of RNase4 gene.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q953
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1 董哲;翼手目核糖核酸酶4基因（RNase4）的分子进化研究[D];云南大学;2016年
，本文编号：2250939
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