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Phylogeography of Hippophae Tibetana

Author: LiuTengZuo
Tutor: LiuJianQuan
School: Lanzhou University
Course: Ecology
Keywords: Phylogeography Quaternary glacial Glacial refuge Exotic differentiation Coalescent simulation
CLC: S793.6
Type: Master's thesis
Year: 2009
Downloads: 263
Quote: 3
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Abstract

Repeated changes in the global climate, especially the Quaternary Ice Age had a significant impact on the geographic distribution of the species and the genetic structure of the Qinghai-Tibet Plateau. The evolutionary history of the species of the region, still there are more controversial. Using chloroplast DNA (cpDNA) and ribosomal DNA (rDNA) two genome molecular markers phylogeography of endemic species of Qinghai-Tibet Plateau, Tibet seabuckthorn (Hippophae tibetana). cpDNA in angiosperms mostly maternally inherited its variants are widely used to explore the history of the formation of the population of a species, the status of gene flow between populations and gas caused by changes in the spatial and temporal patterns of population fragmentation and migration routes; rDNA internal transcribed spacer District (Internal transcribed spacer, ITS) due to the faster rate of evolution, sequencing difficulty small molecular systematics has become, especially lower taxa phylogenetic relationship of the most widely used in a nuclear gene markers. The area of ??distribution of sea buckthorn in Tibet 17 natural populations of 153 individuals cpDNA trnL-F and trnS-G fragment rDNA ITS region was sequenced. Preliminary identification based on sequence variation the cpDNA haplotype geographic distribution pattern, two genome phylogenetic relationships, and then analyzes the changes in the population of a species and intraspecific differentiation process. The two sets of cpDNA sequences were identified of nine kinds haplotype (H1-H9), ITS sequence variation detected a total of 23 kinds of ITS types (I01-I23). The phylogenetic tree was constructed based on chloroplast haplotypes and ITS type showed a consistent topology. The system tree were clustered into two sticks, one corresponding to the distribution of populations in the western Tibetan Plateau (1-5), while the other branch corresponds populations (6-17) in the eastern region. The chloroplast sequence things two groups asked no shared chloroplast haplotypes or ITS type between the two groups and the presence of the difference of at least seven sites. AMOVA analysis showed that the variation between the western populations (1-5) and eastern populations (6-17) accounted for 89.77% of the total variance, little genetic differentiation in the door within the group and the amount of variation to the total variation 6.4%. High index of population genetic differentiation (G _ST = 0.814, N _ST = 0.944), the obvious pedigree structure (N _{ST > G _ST, P <0.001). These results show that Tibet sea buckthorn species exist significant intraspecific differentiation but the species in the glacial plateau mesa high altitudes (> 3,500 m) there are two to more than one refuge. MESQUITE software coalescent simulation results not only support the Tibet seabuckthorn conclusion that there are at least two glacial refuge in the Qinghai-Tibet Plateau, and two things the differentiation occurred 130,000 years ago. The research results show that the Quaternary glaciation of Tibet seabuckthorn species genetic structure had a significant impact, Qilian juniper and Qinghai spruce Qing Zang plateau species with previously published glacial Tibet the seabuckthorn not to migrate the edge of the eastern plateau region , but be able to survive in the refuge of the plateau countertop. Therefore, the Tibetan Plateau evolution of species may not be in accordance with a single mode, the study reveal the the Tibetan Plateau biological species lineage evolutionary history provides important evidence.}

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