NWIPB OpenIR
青藏高原银露梅的谱系地理结构研究
其他题名Phylogeographic structure of Potentilla glabra L. (Rosaceae) on Qinghai-Tibetan Plateau
王留阳
学位类型博士
导师刘建全
2009-05-25
学位授予单位中国科学院西北高原生物研究所
学位授予地点西北高原生物研究所
关键词银露梅 遗传多样性 种群动态 青藏高原 第四纪冰期 避难所
摘要青藏高原地区植物物种遗传多样性的空间分布格局和有效种群变化历史与 第四纪气候变迁密切相关。研究青藏高原区域内植物物种的遗传结构、空间分布 格局和有效种群时空增长式样对于理解该地区过去环境变化和植物遗传资源保 护具有重要意义。银露梅(Potentilla glabra L.)是蔷薇科委陵菜属一种多年生落叶 灌木,连续分布于青藏高原的中心台面到东部南部边缘地区,是研究物种遗传多 样性和青藏高原第四纪气候关系的理想物种。本论文利用母系遗传的叶绿体 DNA 序列标记,研究了青藏高原地区银露梅的遗传结构和遗传多样性分布式样, 追溯了现代种群的有效种群变化历史和当前遗传多样性分布格局形成原因,并结 合青藏高原第四纪气候变迁历史提出了银露梅第四纪冰期的可能避难所,最后还 探讨了青藏高原第四纪是否存在统一大冰盖这一在地质学界长期争论的话题。 本文中通过对银露梅的16 个居群共101 个体(覆盖了青藏高原台面和高原边 缘地区)的叶绿体trnT-L 内含子间隔序列进行了序列测定,共得到31 种单倍型, 除三种单倍型(H5、H2 和H6,均位于分支A 上)出现在2 个及以上居群外,其他 28 种单倍型则只在单一居群中被发现。AMOVA 分析表明银露梅的遗传分化主 要存在于居群内(69.25%)。遗传距离和地理距离没有显著的相关性,NST(0.864) 与GST(0.720)差异不显著,表明银露梅不存在一个显著的谱系地理结构。 系统发育分析和NETWORK 分析均支持所有单倍型聚为三个分支(A,B 和 C),不同分支所包含的单倍型没有明显的地域界限,而且每个分支的单倍型均包 含了青藏高原边缘和高原台面。其中,分支A 包括13 居群11 种单倍型;分支B 包含7 个居群16 种单倍型;分支C 位于系统发育树的基部,包含3 居群4 单倍 型。我们用MISMATCH、Fu’s FS 和‘g’ 检验(种群增长指数)对三个分支分别做了 种群增长动态分析,三个指标的分析结果均支持银露梅在第四纪中发生过两次明 显的种群爆发,即分支A 和B,分别发生在大约20 和31 万年前。 尽管本研究涉及的样本量和居群数有限,但这些结果仍然能够表明银露梅经 历了反复的种群扩张,在末次间冰期前便已占领了青藏高原台面和边缘区域。银露梅种群存在至少两个冰期避难所,即青藏高原台面地区囊谦及邻近区域(即居 群12,13 所在地区及附近地区)和青藏高原东南边缘,即横断山脉区域(居群14, 15 和16 所在地区),这两个地区各自包含了三个分支的12 和8 种叶绿体单倍型, 可能是银露梅在第四纪剩余几次冰期中的可能避难所。随后几次冰期中,仍有少 量银露梅个体存留在青藏高原台面上。
其他摘要The Quaternary climate-driven population dynamics deeply modified the current distribution and genetic diversity in many plant species in the Qinghai-Tibetan Plateau (QTP). Deciphering the genetic distribution patterns and historical processes of plant species within this region gave rise to valuable information about how the past geographical or climate variations affect the population history, as well as to a new sight on plant conservation population level. Potentilla glabra Lodd. (Rosaceae) is one small deciduous shrub plant occurring widely in the QTP platform and edges, and should be a prior plant to recover the historical relationship between the Quaternary climate oscillations and population dynamics. In present study, we mapped the genetic diversity and simulated the population dynamic processions of P. glabra based on the matrilineal chloroplast DNA variations, with purpose to reveal its evolutionary history and spatial distribution changes affected by past cooling/warm climate oscillations, as well as to find the possible refugia in the glacial stages and further to provide evidence of that whether there is massive ice-sheet in the Quaternary glaciers in the QTP. In total, we recovered 31 haplotypes based the trnT-L fragment variations within 101 individuals from 16 populations which cover the both interior and edge of QTP. Three haplotypes from clade A occurred more than two populations, i.e H2, H5 and H6, while the remnant 28 haplotypes were private for only special population. AMOVA analyses revealed the most genetic variations (69.25%) were distributed in the within populations, and insignificant phylogeographic structure of the sampled populations was found by both SAMOVA and comparisons of NST (0.864) and GST (0.720). Phylogenetic and network analyses of the recovered 31 haplotypes identified three tentative clades (A, B and C), all of which had no distinct geographic range. The clades A and B containing 27 haplotypes with a star-like phylogeny are distributed across most of the sampled populations while clade C with four haplotype was fixed only in three disjunct populations. Based on the hierarchical mismatch analysis, two independent range expansions within clades A and B were recovered and estimated to be approximately 316 and 201 thousand years ago (kya). These expansions were also confirmed by the significant negative Fu’s FS values and strongly increased population sizes suggested by ‘g’ tests. Although the samples in the present study were only collected from the edge and platform regions located in the northeastern and southeastern QTP and the available samples are limited, our finding suggested that multiple refugia (especially during LGM) were maintained for this species at both the edge and the platform of the plateau. In response to the climatic oscillations, this species had experienced repeated range expansions across most of the sampled populations. It is obvious that P. glabra had also endured the following glacial ages (for example, LGM) in these populations.
页数90
语种中文
文献类型学位论文
条目标识符http://210.75.249.4/handle/363003/3226
专题中国科学院西北高原生物研究所
推荐引用方式
GB/T 7714
王留阳. 青藏高原银露梅的谱系地理结构研究[D]. 西北高原生物研究所. 中国科学院西北高原生物研究所,2009.
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