中国红豆杉属分子谱系地理学与遗传多样性研究

发布时间：2018-03-07 21:51

本文选题：红豆杉属　切入点：分子谱系地理学　出处：《中国林业科学研究院》2016年博士论文　论文类型：学位论文

【摘要】：中国的红豆杉属(Taxus L.)植物资源丰富,分布广泛,中国植物志(1999)中记载有三种两变种。由于人们过度开发利用,已经处于濒危状态。因此了解红豆杉属植物天然群体的遗传多样性及遗传结构对于评价和保护红豆杉属的遗传资源具有重要理论价值。红豆杉属植物是第三纪孑遗物种,因此分子谱系地理学研究将为研究红豆杉属遗传多样性形成机制及推断该属物种迁移演化历史提供依据。本论文选取全中国范围内的红豆杉属各种典型分布区植物样本,开发并筛选出富含多态性的微卫星标记用于不同种群遗传多样性及遗传结构分析,同时开展了基于4个质体DNA序列片段和1个核基因片段的基因变异来分析国内现存5种红豆杉(包括变种)的谱系地理关系及遗传多样性水平,从而推测种群的历史动态,为制定遗传资源的保护策略提供理论依据。主要研究成果如下:(1)红豆杉属植物64个种群具有较高水平遗传多样性。联合的叶绿体序列片段得到44个单倍型,总的单倍型多样性Hd=0.7368,总的核苷酸多态性π=0.00396;线粒体基因片段检测出6种单倍型,整体的单倍型多态性Hd=0.4660,核苷酸多态性π=0.00066,HT=0.451。其中,东北红豆杉HT=0.662,须弥红豆杉复合类群HT=0.819;基于ITS基因序列检测出73种单倍型,总体水平的单倍型多样性Hd=0.9143,核苷酸多样性π=0.00891,总的遗传多样性HT=0.813。其中,东北红豆杉HT=0.750,须弥红豆杉复合类群HT=0.831;12对SSR引物检测我国红豆杉41个种群的遗传多样性,共检测288个等位基因,平均每个等位基因数为19.244个,平均期望杂合度He=0.479,且群体内的基因多样度(Ht)的平均值为0.498大于群体间的基因多样度(Hs)的平均值为0.282。综合比较,西南地区的横断山区和秦岭-大巴山区表现出高的遗传多样性,华东地区和华中地区及东北长白山区均表现相对较低的遗传多样性。(2)AMOVA分析遗传结构表明,基于质体DNA序列分析结果为种群间遗传变异显著大于种群内的遗传变异,而基于核基因(ITS序列和nrSSR标记)分析结果为种群内的遗传变异大于种群间遗传变异水平。主要因为国内红豆杉属植物为雌雄异株,其叶绿体DNA和线粒体DNA都是父系遗传,表现花粉流,而因其无花粉囊的花粉结构及处于林下次层林的特征,阻碍了花粉的传播而限制了花粉流,使得种群间变异大于种群内的遗传变异。而核基因遗传表现为种子流,红豆杉属植物的果实味道香甜,颜色鲜艳,深得部分鸟类的喜爱,从而得到长距离传播,促进了种子流,而降低了种群间的分化。(3)本研究检测到了红豆杉属植物的种群具有明显的谱系结构(核基因:GST=0.412,NST=0.792;叶绿体基因:GST=0.7840,NST=0.8280),NST均显著大于GST(P0.001),从单倍型的严格一致性树和network图也可以看出,不同地区的单倍型得到较好的聚类,且Mantel检验结果也表明,红豆杉属植物的种群间的遗传距离与地理距离之间有显著的相关性,这也就表明红豆杉属植物的种群间也存在一定的地理隔离影响,这也是红豆杉属植物的种群间遗传分化和具有明显的谱系地理格局的重要原因。(4)种群历史上是否经历过扩张的检验结果表明,Tajima’s D检验表明符合中性突变进化,而失配分析的结果也未检测到红豆杉属植物种群经历过近期扩张,只有长白山区的失配分析曲线图表现为单峰,说明长白山区的种群可能经历了扩张。而从本研究所得的单倍型分布规律上看,主要存在两种形式,其一很多种群都具有其独特单倍型,其二,一些种群共享同一种单倍型,这些很有可能表明红豆杉分布区经历过异域片段化,存在多个避难所。
[Abstract]:Chinese Taxus (Taxus L.) is rich in plant resources, wide distribution, flora Chinese (1999) there are three species and two varieties recorded. Due to excessive exploitation of people, are already endangered. So understanding the genetic diversity of natural populations of Taxus plants and genetic structure has important theoretical value for the evaluation of genetic resources and the protection of Taxus. Taxus is the third century relic species, so the research of molecular phylogeography for research on genetic diversity of Taxus species inferred that the formation mechanism and evolution history of migration and provide the basis. This paper selects the Chinese within the scope of all kinds of typical plants of the genus Taxus distribution samples, developed and selected micro microsatellite polymorphism rich for different population genetic diversity and genetic structure, and carry out the 4 plasmid DNA sequence fragment and 1 nuclear based for tablets Analysis of the existing 5 kinds of genetic variation of Taxus chinensis (including varieties) of the phylogenetic relationship and genetic diversity level, which suggested that the historical population dynamics, provide a theoretical basis for the protection strategy of genetic resources. The main research results are as follows: (1) the 64 populations of Taxus plants have a high level of genetic diversity. The obtained fragment combined with chloroplast sequences of 44 haplotypes, the haplotype diversity of Hd=0.7368, =0.00396 of the total PI nucleotide polymorphism; mitochondrial gene fragments detected 6 haplotypes, overall Hd= haplotype polymorphism 0.4660 nucleotide polymorphism, =0.00066, HT=0.451., HT=0.662 yew, Taxus wallichiana compound group HT=0.819; ITS gene sequence detected 73 haplotypes based on the overall level of Hd=0.9143 haplotype diversity, nucleotide diversity of PI =0.00891, the total genetic diversity of HT=0.813. In HT=0.750, yew, Taxus wallichiana compound group HT=0.831; 12 pairs of SSR primers to detect 41 of China's population genetic diversity of Taxus chinensis, were detected 288 alleles. The average allele number was 19.244, the average expected heterozygosity of He=0.479, and the gene diversity within populations (Ht) average a value of 0.498 was higher than that of inter population gene diversity (Hs) 0.282. comprehensive comparison is the average of the southwestern region of the Hengduan Mountains and Qinling Mountains Daba Mountains showed high genetic diversity in East China and central China and northeast Changbai Mountain region showed relatively low genetic diversity. The genetic analysis of AMOVA (2) the structure shows that the plastid DNA sequence analysis results of genetic variation among populations was significantly greater than the genetic variation within populations based on, based on nuclear gene (ITS sequence and nrSSR marker analysis) results among populations left for genetic variation within populations than The level of genetic variation. Mainly because the domestic Taxus plants dioecious, the chloroplast DNA and mitochondrial DNA is paternal inheritance, expression of pollen flow, and because of its no pollen sac and pollen structure and characteristics in the forest next storied, hindered the spread of pollen restricted pollen flow, the variation among populations greater than the genetic variation of population the nuclear gene expression. The genetic flow of Taxus seeds, fruit sweet taste, bright color, deep part of the bird's favorite, resulting in long distance transmission, promote the seed flow, and reduce the differentiation among populations. (3) pedigree structure obviously detected in this study of the genus Taxus the population (with nuclear genes: GST=0.412, NST=0.792; GST=0.7840, NST=0.8280: chloroplast genes), NST were significantly higher than that of GST (P0.001), from the strict consensus tree and haplotype network map can also be seen in different regions The haplotype has better clustering, and Mantel test results also show that there is a significant correlation between the genetic distance and geographic distance among the populations of Taxus species, suggesting that it will affect the existence of geographic isolation of Taxus species, the genetic differentiation is red bean fir species populations and important why has the obvious phylogeographic pattern. (4) whether the population history experienced expansion of test results showed that Tajima s D test showed that the neutral mutation evolution, and the mismatch analysis results also did not detect the yew species populations experienced a recent expansion, only the Changbai Mountain area mismatch analysis curves showed a single peak, Changbai Mountain district population may have experienced expansion. From this study, the haplotype distribution law point of view, there are two main forms, one is multi group has its The unique haplotype, the second, some populations share the same haplotype, which is likely to indicate that the Taxus distribution area has experienced a foreign region fragmentation, and there are many shelters.

【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S791.49

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