NWIPB OpenIR
麻花艽的谱系地理分析
其他题名Phylogeography of Gentiana straminea (Gentianaceae)
谌平
学位类型硕士
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
关键词青藏高原 麻花艽 叶绿体 Dna Trns-trng 谱系地理学 冰期避难所
摘要第四纪气候变迁影响和奠定了目前动植物的地理分布格局和遗传结构。但第四纪气候变化如何影响青藏高原动植物遗传多样性分布,目前仍不清楚。麻花艽(Gentiana straminea) 隶属于龙胆科(Gentianaceae)龙胆属秦艽组(Gentiana sect. Cruciata),是一种多年生草本植物,广泛分布于青藏高原及其周边地区,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片段(trnS-trnG)对麻花艽进行谱系地理学研究,分析了青藏高原地区麻花艽种群的遗传结构和遗传多样性分布式样,并结合青藏高原第四纪气候变迁历史推测麻花艽第四纪冰期的可能避难所以及冰期后的回迁路线。 本论文对麻花艽22个居群共193个个体的trnS-trnG片段进行了测序,其长度为553 bp,共发现了4个单核苷酸变异位点,没有发现插入/缺失片段,这些变异位点共鉴定出5种单倍型,即H1-H5。其中单倍型H1和H2分布于高原边缘和台面上大量居群中,尤其是H1,仅在居群4和居群7没有发现。而H3,H4,H5这三种单倍型只发现高原台面居群,即居群5-9。AMOVA分析表明多数遗传变异(51.35%)存在于居群内,而居群间的变异也较高(48.65%)。遗传分化系数Nst(0.530)并没有显著大于 Gst(0.516),说明麻花艽的叶绿体单倍型的谱系地理结构不明显;使用SAMOVA软件对麻花艽居群进行分组,没有得到有意义的k值,同样支持遗传距离与地理距离没有显著的相关性。 居群5-9位于青藏高原台面上,包含了全部5种单倍型,具有最高的单倍型组成和遗传多样性,其中H3,H4和H5为该地区的特有单倍型;该地区应该是麻花艽重要的遗传多样性中心,是末次最大冰期(LGM,距今约2万年)的避难所之一。而这些居群的海拔均超过4000 m,说明在末次最大冰期时仍有麻花艽个体存留在这些地区。东部边缘居群只包含单倍型H1和H2,并没有其它单倍型,应该是冰期气候变迁中由于奠基者效应和瓶颈效应导致遗传多样性降低。
其他摘要The Quaternary climate and environment oscillations have played important roles in shaping the current spatial distribution of most species in Qinghai-Tibetan Plateau (QTP). However, how Quaternary climatic oscillation affected the patterns of spatial distribution and genetic structure of alpine species in QTP is still largely unknown. Gentiana straminea (Gentianaceae) is a widely distributed herb species in the QTP and adjacent area. In order 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, we mapped the genetic diversity and simulated the population dynamic processions of G. straminea based on the maternally inherited chloroplast DNA (cpDNA) (trnS-trnG) sequence variations. We recovered 5 haplotypes (H1-H5) in 193 individuals from 22 natural populations which covered all the distribution region of QTP. The most common haplotype H1 was found in 112 individuals (58.03% of the total samples) and distributed in all but two populations (population 4 and population 7). The second abundant haplotype H2, including 64 individuals, was found in 12 populations. The third one H5 distributed in four adjacent populations with 14 individuals. The remaining two haplotypes included very few individuals. Respectively, H3 distributed in population 6 and population 8, while H4 only fixed in population 8. Analysis of molecular variance (AMOVA) revealed that more than half of the total genetic variation was found within populations (51.35%), while genetic differentiations between populations was obviously distinct (Fst = 0.4865). Both SAMOVA analysis (failed to detect any meaningful geographical groups) and PERMUT calculated result (Nst=0.530, Gst=0.516; Nst was not significant larger than Gst, P>0.05), suggesting there was no significant phylogeographical structure. The high diversity in the central QTP and endemic haplotypes of G. straminea occurring there suggested this area had served as one of important refugia during the Quaternary glacial ages. Our data indicated that this species survived in the Last Glacial Maximum (LGM) in the central plateau, which supported the assumption that there was “no mass ive ice-sheet on the QTP” at least during the Last Glacial Maximum.
页数42
语种中文
文献类型学位论文
条目标识符http://210.75.249.4/handle/363003/3278
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
谌平. 麻花艽的谱系地理分析[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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