题名 | 窄叶鲜卑花分子系统地理学研究 |
作者 | 段义忠 |
学位类别 | 博士 |
答辩日期 | 2010-06 |
授予单位 | 中国科学院研究生院 |
授予地点 | 北京 |
导师 | 陈世龙 |
关键词 | 窄叶鲜卑花 叶绿体DNA 核糖体DNA 冰期避难所 分子系统地理学 青藏高原 |
学位专业 | 生态学 |
中文摘要 | 青藏高原是世界上最高最大的高原,第四纪冰期气候的反复变化应对高原生 |
英文摘要 | The Qinghai-Tibetan Plateau (QTP) is the highest and largest plateau in the world. The topological effect of the Qinghai-Tibetan Plateau during the Quaternary climatic oscillations must have important effects on the adaptive radiations, isolated evolution and speciation of species on the QTP. Therefore, the QTP is becoming a hot area and model region for the research of biological evolution. Sibiraea angustata belonging to the genus Sibiraea L. of family Rosaceae, is a perennial shrub widely distributed on the QTP and adjacent regions. In this study, phylogeographical research of this shrub species was conducted to reveal its evolutionary history and spatial distribution changes affected by past climate oscillations, as well as to find the possible refugia in the glacial stages. Two chloroplast DNA (cpDNA) intergenic spacers (trnS-trnG and rpl20-rps12) and nrDNA ITS intergenic spacer were amplified and sequenced in 493 individuals from 40 populations sampled from the entire distribution range of Sibiraea angustata. The main results are as follows: 1) Eight haplotypes were identified for the cpDNA trnS-trnG fragment and six for the rpl20-rps12, after the combination of the trnS-trnG and rpl20-rps12 sequences, 19 haplotypes were recovered. Only a few ancenstral haplotypes (e.g. H1 detected in the trnS-trnG intergenic spacer; H5 in the rpl20-rps12 intergenic spacer; H5 in the combined sequences) were common and widespread throughout the distributional range of S. angustata. Most haplotypes were restricted to single sites or to neighbouring populations. Populations from the southeastern margin of the QTP owned high haplotype diversity and/or nucleotide diversity and fixed more private haplotypes, which suggested that the southeastern margin of the QTP was an important S. angustata refugium during the Quaternary glaciation. Populations from Yushu and its adjacent region of the QTP platform also owned high haplotype diversity and/or nucleotide diversity, which suggested that Yushu and its adjacent region of the QTP might be another potential refugium for S. angustata during the Quaternary glaciation. 2) We recovered 5 haplotypes based on the nrDNA ITS fragment variations in 318 individuals from 40 populations covering the both platform and edge of QTP. Only one ancenstral haplotype (H2 detected in the nrDNA ITS intergenic spacer) were common and widespread throughout the distributional range of S. angustata. Most haplotypes were restricted to single sites or to neighbouring populations. Populations from the southeastern margin of the QTP owned high haplotype diversity and/or nucleotide diversity and fixed more private haplotypes, which farther suggested that the southeastern margin of the QTP was an important S. angustata refugium during the Quaternary glaciation. 3) Analyses based on the combined sequences of the trnS-trnG and rpl20-rps12 intergenic spacers showed that total gene diversity was especially high (HT = 0.796)and average gene diversity within populations was relatively low (HS = 0.204). The estimates of interpopulation differentiation were high (GST = 0.744,NST = 0.855), NST. > GST suggested significant phylogeographical structure. Analysis of molecular variance (AMOVA) showed that the genetic variation mainly resided among populations (84.07%) and the FST was 0.809. The average gene flow among populations was 0.106. Analyses based on the nrDNA ITS sequences showed that total gene diversity was especially low (HT = 0.257) and average gene diversity within populations was relatively low (HS = 0.153). The estimates of interpopulation differentiation were low (GST = 0.406,NST = 0.293), Analysis of molecular variance (AMOVA) showed that the genetic variation mainly resided among populations (62.55%) and the FST was 0.374. The average gene flow among populations was 0.83. 4) Nested clade analysis (NCA) indicated that the main historical event acted on the total cladogram was long distance colonization possibly coupled with subsequent fragmentation or past fragmentation followed by range expansion. Before the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary glaciation, some ancient haplotypes was distributed across the entire former range of this species. During glaciation, continuous populations of S. angustata were fragmented into several geographically isolated populations which survived in isolated refugia located at the southeastern margin and the Yushu and its adjacent region of the QTP. During interglacial and postglacial periods, population experienced local expansion, Fouder effect occurred during the population expansion which lead to the low level of genetic diversity and haplotype on the plateau platform. |
语种 | 中文 |
学科主题 | 生物科学 |
公开日期 | 2012-05-10 |
内容类型 | 学位论文 |
源URL | [http://ir.nwipb.ac.cn/handle/363003/3392] |
专题 | 西北高原生物研究所_中国科学院西北高原生物研究所 |
推荐引用方式 GB/T 7714 | 段义忠. 窄叶鲜卑花分子系统地理学研究[D]. 北京. 中国科学院研究生院. 2010. |
个性服务 |
查看访问统计 |
相关权益政策 |
暂无数据 |
收藏/分享 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。
修改评论