翼手目核糖核酸酶4基因（RNase4）的分子進(jìn)化研究
發(fā)布時(shí)間：2018-09-19 18:17
【摘要】：核糖核酸酶基因(RNase A)超家族作為脊椎動物所特有的基因家族是分子進(jìn)化研究的重要模型。該基因家族因頻繁的基因復(fù)制和假基因化事件而在不同物種中存在不同的基因數(shù)量,從而產(chǎn)生了功能分化。2013年,Goo等對哺乳動物核糖核酸酶基因(RNase A)超家族各成員的分析中發(fā)現(xiàn)其中的RNase4基因在翼手目中的Yinpterochiroptera亞目代表物種--馬來大狐蝠(Pteropus vampyrus)有一個功能基因,而在Yangochiroptera亞目代表物種--瑩鼠耳蝠(Myotis lucifugus)中有12個基因,發(fā)生了基因復(fù)制現(xiàn)象。提示RNase4基因在翼手目中可能具有特殊的進(jìn)化模式和功能分化。而RNase4基因在翼手目中的其他物種中是否發(fā)生了基因復(fù)制,發(fā)生復(fù)制的時(shí)間及驅(qū)動力等都需要增加翼手目更多代表物種進(jìn)行深入研究。本研究收集了翼手目兩個亞目(Yinpterochiroptera 和 Yangochiroptera)五個超科(菊頭蝠超科,狐蝠科,蝙蝠超科,鞘尾蝠超科和兔唇蝠超科)的9科25屬28個物種,進(jìn)行RNase4基因的分子進(jìn)化研究。研究結(jié)果發(fā)現(xiàn)RNase4基因在Yangochiroptera亞目蝙蝠超科的蝙蝠科物種中發(fā)生了基因復(fù)制,而在其他研究的物種中,除了Yinpterochiroptera亞目狐蝠科的中央狐蝠中只檢測到一個假基因外,其余都只檢測到一個功能基因。中央狐蝠RNase4假基因化表明該基因在該物種中可能不具功能。系統(tǒng)發(fā)育研究結(jié)果表明蝙蝠科首先在祖先枝經(jīng)歷了一次基因復(fù)制事件,然后經(jīng)歷了一次假基因化事件。蝙蝠科中的鼠耳蝠屬發(fā)生了大量的基因復(fù)制,而且以基因的形式聚集成簇,經(jīng)歷了至少兩次基因復(fù)制。分歧時(shí)間估算也表明該基因復(fù)制發(fā)生在物種形成之前。此外,蝙蝠科的黃蝠屬中的基因復(fù)制則發(fā)生在物種形成之后,為非常近期的一次基因復(fù)制。選擇分析中的“位點(diǎn)特異”模型(site-specific model)檢測到14個正選擇位點(diǎn),其中位點(diǎn)76(Q76E)和98(Q98K)都位于活性位點(diǎn)附近,推測其可能會通過影響核糖核酸酶4酶活性及底物結(jié)合活性產(chǎn)生功能改變。此外,選擇分析中的“枝-位點(diǎn)”(branch-site model)模型在蝙蝠科中發(fā)生基因復(fù)制的B基因簇祖先枝中檢測到顯著的正選擇信號及兩個正選擇位點(diǎn)(58和73)。以上研究結(jié)果表明蝙蝠科RNase4在適應(yīng)性選擇作用的驅(qū)動力下發(fā)生基因復(fù)制,并有可能產(chǎn)生了功能分化。本研究通過對翼手目更多代表物種的RNase4基因分子進(jìn)化分析,揭示了翼手目RNase4基因復(fù)雜的進(jìn)化模式,為后續(xù)的RNase4基因的功能研究提供了重要的理論依據(jù)。
[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.
【學(xué)位授予單位】：云南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：Q953
本文編號：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.
【學(xué)位授予單位】：云南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：Q953
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相關(guān)碩士學(xué)位論文 前1條
1 董哲;翼手目核糖核酸酶4基因（RNase4）的分子進(jìn)化研究[D];云南大學(xué);2016年
，本文編號：2250939
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