本文選題：淡水龜　切入點：線粒體DNA　出處：《安徽師范大學》2016年博士論文

【摘要】：淡水龜科廣義擬水龜屬(Mauremys sensu lato)物種廣泛分布于歐亞大陸。由于特殊的分布模式,其物種間的系統(tǒng)發(fā)生學一直是研究的熱點。前人關于該類群的分子學研究多數(shù)是采用部分線粒體基因或核基因,不同分子學標記所得的結論存在爭議,且該屬物種的系統(tǒng)地理學以及物種起源的研究也仍處于空白。線粒體基因組具有高突變率,低重組率以及嚴格母系遺傳等特質,常被作為理想的分子標記,廣泛應用于生物的起源以及系統(tǒng)發(fā)生學關系的研究中。由于相對較快的進化速率,線粒體DNA的進化一直被認為不受選擇壓力的調控。然而,隨著細胞能量代謝領域的不斷深入研究,已明確線粒體DNA編碼的蛋白在氧化呼吸電子傳遞過程中具有重要的作用,線粒體DNA的變異受到了選擇壓的調控。研究表明,線粒體DNA的突變與多種疾病密切相關。龜類物種線粒體基因組在基因結構上相對保守,僅在部分物種中出現(xiàn)了控制區(qū)倍增和蛋白編碼基因位移的現(xiàn)象。這種特異型的線粒體基因組進化動力學以及其受到的選擇壓調控機制仍有待進一步研究。本研究通過測定地中海擬水龜(M.leprosa)、里海擬水龜(M.caspica)、希臘擬水龜(M.rivulata)和黃喉擬水龜(M.mutica)的線粒體全序列,結合NCBI上已有的序列數(shù)據(jù),基于最大似然法(Maximum likelihood,ML),貝葉斯法(Bayesian inference,BI)重建廣義擬水龜屬內物種系統(tǒng)發(fā)生樹;使用化石記錄標定,推算該屬物種分歧時間;結合相關地理學事件,重建祖先起源地。結合陸龜科、鱉科和淡水龜科相關物種ND5基因序列,通過熒光定量PCR技術和生物信息學分析,探討龜類動物特異型的線粒體基因進化模式及其相關的適應性機制。研究的主要結果和結論如下:1、擬水龜屬系統(tǒng)發(fā)生分析結果表明,原按形態(tài)學比較劃分的四個屬,烏龜屬(Chinemys)、花龜屬(Ocadia)、擬水龜屬(Mauremys)和安南龜屬(Annamemys)之間有著密不可分的并系關系,建議將原四屬物種合并入一個擴充的屬,即廣義擬水龜屬(Mauremys sensu lato)。分歧時間和祖籍地重建結果顯示東南亞可能是該屬物種最早的起源地,后期的物種形成過程中遺傳漂變作用起到了主導地位。日本擬水龜?shù)姆制缈赡芷鹨蛴谌毡緧u嶼化活動。多態(tài)微衛(wèi)星分析結果表明,東亞和東南亞擬水龜種群間沒有明顯的分化,可能存在廣泛的雜交事件發(fā)生。線粒體分析結果和微衛(wèi)星結果的不一致性,支持東南亞的黃喉擬水龜可能是雜交起源。2、截至2016年3月,已完成測序并釋放的龜鱉動物線粒體全序列共有115條,涉及龜鱉目11個科,61個種。大多數(shù)龜類動物的線粒體基因組在基因結構上相對保守,然而部分物種中出現(xiàn)了控制區(qū)倍增和蛋白編碼基因位移的現(xiàn)象。研究通過比較具有典型脊椎動物線粒體基因組特征的烏龜線粒體DNA以及高度變異的平胸龜線粒體DNA,采用實時定量PCR技術進行相對定量,探討ND5基因位置轉移以及控制區(qū)倍增對龜類動物線粒體基因表達量的影響。結合陸龜科、鱉科和淡水龜科相關物種ND5基因序列,估算高度變異的線粒體DNA所受的選擇壓,并模擬ND5亞基的蛋白質三維結構,探討基因堿基序列的變異對能量代謝的影響。結果表明,與保守龜類動物線粒體DNA相比,高度特異化的線粒體基因組具有關聯(lián)能量代謝的適應性意義。其ND5基因的重排以及控制區(qū)的倍增可能產(chǎn)生了新的線粒體轉錄模式,即雙控制區(qū)線粒體共有三個轉錄啟動始點,分別起始轉錄三條不同長度的轉錄本,通過ND5基因原初轉錄產(chǎn)物長度的縮短,導致其表達量的上調。而高水平的非同義替代率,可能增加了ND5蛋白的跨膜面積,從而增強其為合成ATP供給能量的能力。綜上所述,本研究闡明了淡水龜科擬水龜屬物種的系統(tǒng)發(fā)生關系以及歷史性起源、物種形成事件,評估東亞東南亞擬水龜?shù)幕蛄魉?進一步探討其種間雜交程度。并通過分析龜類動物線粒體蛋白編碼基因ND5的進化,探討部分物種特異型的線粒體基因進化模式及其相關的適應性機制。
[Abstract]:Generalized quasi Clemmys Bataguridae (Mauremys sensu lato) species widely distributed in Eurasia. The specific distribution pattern, the system of species occurrence has been a focus of research. The previous studies on the molecular groups is the most part of mitochondrial genes or nuclear genes with different molecular markers, the conclusion is controversial the phylogeography of the origin of species and genus species are still blank. The mitochondrial genome has a high mutation rate, low recombination rate and strict maternal genetic traits, is often regarded as the ideal molecular markers, has widely used in biological origin and study the relationship between system. Due to the relatively fast rate of evolution, mitochondrial DNA evolution has been considered not be regulated by the selective pressure. However, with the deepening of research in the field of cellular energy metabolism, mitochondrial DNA has been clear Encoding protein plays an important role in the oxidative respiratory electron transfer process by regulating mitochondrial DNA variation in selection pressure. The results show that the mitochondrial DNA mutation associated with many diseases. The turtle species mitochondrial genome is conserved in the gene structure, only in some species appeared in the control area of multiplication and protein encoding the gene displacement phenomenon. The mitochondrial genome of the evolutionary dynamics of this specific type and selection by pressure regulation mechanism still needs further research. In this study, through the determination of Mediterranean turtle (M.leprosa), where the sea turtle turtle (M.caspica), Greece (M.rivulata) and mauremysmutica (M.mutica) of the complete sequence of mitochondrial, combined with the sequence data already on the NCBI, based on the maximum likelihood method (Maximum, likelihood, ML), (Bayesian inference, BI Bayesian method) reconstruction of generalized quasi species Clemmys system The occurrence of trees; use of fossil record calibration, the time between species differences; combined with the geography event, reconstruction of ancestral origin. Combined with the tortoise branch, kinosternidae Bataguridae and related species ND5 gene sequence by fluorescence quantitative PCR and bioinformatics analysis on mitochondrial gene evolution model for turtle animal specific type and the adaptive mechanism. The main research results and conclusions are as follows: 1, to Clemmys system analysis results show that the original four genera according to the morphological comparison of the division, the tortoise (Chinemys), is a flower turtle (Ocadia), quasi Clemmys (Mauremys) and Annan (Annamemys) between the turtle a close relationship and, suggested that the four species of the genus into an extended genus, namely generalized quasi Clemmys (Mauremys sensu lato). The different time and the ancestral reconstruction results in Southeast Asia may be the earliest species The origin, the late species form of genetic drift effect plays a dominant position. Japanese turtle differences may arise from the Japanese islands. Microsatellite analysis results show that the quasi East and Southeast Asia, no obvious differentiation of turtle populations, hybridization events may exist widely. Mitochondrial and micro analysis results the satellite is not consistent and support in Southeast Asia may be Huang Houni turtle hybrid origin.2, as of March 2016, has completed the sequencing and sequence of animal mitochondrial release of the turtles had a total of 115, involving testudinata 11 families and 61 species. Most turtles animal mitochondrial genome is relatively conservative in genetic structure, but some the species appeared in the control area and double protein encoding gene displacement phenomenon. Comparing with genomic characteristics of typical vertebrate mitochondrial turtle mitochondrial DNA And the height variation of turtle mitochondrial DNA, relative quantification using real-time quantitative PCR technique, ND5 gene transfer and control of position area double expression of turtle animal mitochondrial gene. Combined with the tortoise branch, kinosternidae Bataguridae and related species ND5 gene sequence, the estimation of mitochondrial DNA was highly variable the selection pressure, and simulate the three-dimensional structure of protein ND5 subunit gene sequence, to explore the influence of variation of energy metabolism. The results showed that compared with the conservative turtle animal mitochondrial DNA, mitochondrial gene was highly specific adaptive significance of associated with energy metabolism. The multiplication of ND5 gene rearrangement and control region may produce a new model of mitochondrial transcription, including mitochondrial double control zones of the three transcription start point, respectively, to initiate transcription of three different lengths of ND5 gene transcripts, through the original Shorten the length of the transcripts, the expression level was raised. And the high level of non synonymous substitution rate may increase the transmembrane area of ND5 protein, thereby enhancing its ability to synthesize ATP supply of energy. In summary, this study elucidates Bataguridae quasi Clemmys relations and historical origin of species occurrence system the speciation events, evaluation of East and Southeast Asia to investigate the level of gene flow, further explore the interspecific hybridization degree. And through the analysis of turtle animal mitochondrial gene ND5 encoding protein evolution, to explore the species specific type of mitochondrial gene evolution model and its adaptability mechanism.

【學位授予單位】：安徽師范大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：Q953

【參考文獻】

相關期刊論文 前1條

1 李吉均,方小敏,潘保田,趙志軍,宋友桂;新生代晚期青藏高原強烈隆起及其對周邊環(huán)境的影響[J];第四紀研究;2001年05期

，

本文編號：1698186