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题名	兔属和盘羊属的分子进化研究
作者	吴春花
学位类别	博士
答辩日期	2005-03
授予单位	中国科学院研究生院
授予地点	北京
导师	张亚平
关键词	兔属（Lepus） 盘羊属（Ovis） 分子系统学 历史生物地理学 云南兔（LePuscomus） 雪兔种组（thetlmidusgrouP） 比较系统地理结构 群体遗传结构 盘羊（Ovisammon） 保护遗传学
其他题名	Molecular Evolution of the genus Lepus and Ovis
中文摘要	兔属物种的形态特征差异甚微，其分类地位长期存在争议。本研究论文来用线粒体DNA标记从分子水平对兔属物种的系统发育，分类地位以及历史生物地理学进行探讨。我们应用四个线粒体DNA标记：细胞色素b和125基因全序列，ND4和控制区部分序列构建中国野兔和世界范围内的其它兔属物种间的系统发育关系。系统发育关系的构建以鼠兔为外群，采用三种方法：最大简约法（淤），最大似然法（ML）和贝叶斯方法（Bl）。分析结果显示：中国野兔并不是一个单系群。世界范围内的兔属动物形成一个单系，并以地理分布可分为相应的三个种组：北美种组（NortoAmericanspeciesgroup），欧亚种组①urasionspeciesgroP）和非洲种组（S。uthAfricanspeciesgroup）。兔属动物鉴定的29个种可能多于该属的有效种。历史生物地理学的祖先地分析表明：兔属动物起源于北美大陆，通过白令大陆桥扩散到欧亚大陆，最后到达非洲大陆。Brooks简约分析（BPA）揭示兔属物种形成是在扩散事件之后，在不同的地理区域适应当时的生态环境导致种的发生。兔属动物经历了一个快速扩散和种发生的过程。贝叶斯放松分子钟方法估计种组内的分化时间显示：兔属物种的形成是在上新世早期（Plioceneepoch：4.29-5.39MyA）。云南兔（L.comusGAllen1927）是仅分布于云贵高原上的唯一一种兔属物种。我们应用线粒体DNA控制区第一高变区检测云南兔的群体遗传结构和系统地理结构模式，评价地理隔离，如高山、河流等对该物种的群体结构和系统地理模式的影响。分子变异分析显示（AMOVA）不同的地理区域间遗传差异明显，而且成对遗传差异与相应的地理距离成线性关系。错配核普酸分析（Mismatchanalysis）表明云南兔群体近期没有群体扩张。系统地理学的嵌套分析法揭示云南兔现有的群体遗传结构和遗传分化与云南高原复杂的地形地貌相关。高山、河流等地理隔离导致群体间有限的基因流形成了现有云南兔群体的分布。云南兔不同地理区域单倍型的分子系统分析以及明显的群体分化建议云南兔两个亚种的划分（L．c．comusandL．c．peni）。雪兔种组（thetimidusspeciescomplex）是生活于北半球高纬度区域的兔属物种。我们以该种组为模型，采用快速进化的mtDNA控制区序列对它们的系统地理结构进行比较研究。结果表明：雪兔种组以白令海峡为地理隔离存在显著的系变异为7．7％，变异范围从2．4％一11．5％。分子系统分析的最大简约树显示：来自乌孜别克斯坦的两个亚种（seertzoviandnikr枷ontana）首先发生遗传上的分化。之后盘羊祖先群体的扩散导致在中国某些地理区域可能有三个进化谱系的分化。盘羊祖先群体的扩散可能起始于亚洲大陆的西部通过中亚高原向南扩散。分布于中国的盘羊亚种中，阿尔金亚种（O.a.dalai-lamae）与西藏亚种（O.a.hodsoni）有着比蒙古亚种（aa．da附ino较近的系统进化关系。而来自乌孜别克斯坦的两个亚种（servertzoviandnigrimontana）与中国的盘羊亚种有着显著的遗传差异。
英文摘要	In spite of several classification attempts within the genus Lepus, phylogenetic relationships still remain poorly understood. Here we present molecular genetic data that help sorts out some of the present incongruities in the phylogeny of the genus Lepus. The complete mitochondrial cytb, 12S genes, and parts of ND4 and control region genes were sequenced to examine phylogenetic relationships within Chinese hare taxa and other Leporids throughout the World using maximum parsimony, maximum likelihood and Bayesian phylogenetic reconstruction approaches. Using reconstructed phytogenies, we observed that the Chinese hare is not a single monophyletic group as originally thought. Instead, the data suggests that the genus Lepus is monophyletic with three unique species groups: North America, Eurasia and South Africa. The data also infers that the 29 Lepus species currently recognized as valid taxa is a gross overestimate of the number that actually exists. Ancestral area analysis indicated that ancestral Lepus arose in North America, and then dispersed into Eurasia via the Bering Land Bridge eventually reaching Africa. Brooks Parsimony analysis (BPA) showed that dispersal events followed by subsequent speciation have occurred in other geographic areas as well and resulted in the rapid radiation and speciation of Lepus. A Bayesian relaxed molecular clock approach based on the continuous autocorrelation of evolutionary rates along branches estimated the divergence time between the three major groups within Lepus. The genus speciation events occurred during the Pliocene epoch (4.29-5.39 MYA). We examined the genetic structure and phylogeographical patterns of the Yunnan hare {L. comus G Allen 1927) by using the first hypervariable domain of the mitochondrial control region genealogies obtained from 22 sampling localities to explain the geographical distributions of the mtDNA haplotypes in this species. A 505-base-pair (bp) segment of the mitochondrial control region was sequenced from 85 individuals representing three morphological recognized subspecies, L. c. comus, L c. pygmaeus and L c. pent. An analysis of molecular variance (AMOVA) shows significant genetic differentiation in the total samples and also between regions. There is a positive correlation between geographic distance and pairwise differences. Mismatch analysis did not indicate that the Yunnan hare populations experienced a recent range expansion. Nested clade analyses revealed significant associations between genetic structure and geographical division, thereby suggesting that restricted gene flow was a major phylogeographical event shaping the geographical distribution of the Yunnan hare in the Yunnan Plateau. Molecular phylogenetic analyses and population genetic structure suggest two subspecies of the Yunnan hare (L c. comus and ?. c. peni) Mitochondrial DNA control region sequence analysis was used to examine the phylogeographical patterns and population structure, the extant of genetic differentiation and their phylogenetic relationships within the timidus species complex (L timidus, L. othus^ L. arctic^ L. capensis and L corsicanus) in the Holarctic. Chinese samples were collected at twelve localities from the origin and distributional center of the Chinese cape hare according to previously comparative studies. Comparison with other Lepus species, the timidus species group has a relative low level of genetic variation. Based on the combined sequence data, phylogenetic analysis for the haplotypes of the timidus species group was constructed using Lepus comus and. L* oiostolus as outgroup. From the tree topology, two clades or phylogeographical groups were identified, and derived from a common ancestor about 0.806-0.242 million years (Myr) ago. However, of the two phylogeographical groups, no obvious phylogeographical structure existed due to the population expansion and the Bering Stait Land Bridge, and also no obvious physical barriers in Chinese mainland. Based upon mitochondrial cytochrome b gene sequence analysis, the history of true sheep Ovis began approximately 3.12 million years ago (MYA). The evolution of the genus Ovis has resulted in three generally accepted groups; namely, Argaliforms, Moufloniforms and Pachyceriforms. The Pachyceriforms of the subgenus Pachyceros comprise the thin-horn sheep 0. nivicola (snow sheep) and O. dalli and the Rocky Mountain bighorn 0. canadensis. North America wild sheep (0. canadensis and 0. dalli) evolved separately from Eurasian wild sheep and diverged from each other about L41 MYA. Ancestral stock that gave rise to snow sheep, Moufloniforms, and Argaliforms occurred 2.3 MYA, which then gave rise to two different extant lines of snow sheep which diverged from each other about 1.96 MYA. The more recent nivicola line is genetically closer to the North American wild sheep and may represent close association during the refugium when Alaska and Siberia were connected by the Bering Land Bridge. The earlier period of evolution of the Pachyceriforms suggest they may have first evolved in Eurasia, the oldest ancestor then giving rise to North American wild sheep, and that a canadensis-liko ancestor most likely gave rise to nivicola. Cytogenetic analysis further validates that the standard diploid number for modern nivicola is 52. Subspecies phylogeny among the argaliform wild sheep (Ovis ammori) has special interest due to its endangered species status and unresolved taxonomic classification. Using a molecular level approach, we fiirther clarify the phylogenetic relationships of several subspecies of ammon by comparing the sequences of mitochondrial DNA in the displacement (D)-loop region. Five putative subspecies of ammon (0. dalai-lamae, 0. darwini, 0. hodgsoni, 0. sairensis and 0. Httledalei) were sampled from four Chinese provinces [Xinjiang, Qinghai, Gansu and XiZang (Tibet)] and two (0. servertzovi and 0. nigrimontana) from Uzbekistan. These samples are representative of most of the currently recognized putative subspecies of argali. mtDNA fragments containing the entire D-loop (approximately 1,100 bases) were amplified by PCR and sequenced. Analysis of mtDNA sequences revealed high variability within ammon (77%), ranging in divergence from 2.4 to 11.52%. Phylogenetic relationships based on Maximum-likelihood (ML) infer that there are two major clades or clusters of argalis: one is the western clade from Uzbekistan and the other the eastern clade of China. Parsimony (MP) analysis show three subclades were identified within the Chinese clade. One subclade includes 0. a. sairensis and 0. a. Httledalei located in Tuoli, Bayinburuke of Xinjiang Prov.; the second subclade consists of only one subspecies (0. a. darwini) from Mazong Mountain, Gansu Prov.; and the third subclade consists of O. a. hodgsoni distributed in Dulan, Qinghai-Tibet plateur, and O. a. dalai-lamae Subei, Gansu Prov.
语种	中文
公开日期	2010-10-15
内容类型	学位论文
源URL	[http://159.226.149.42:8088/handle/152453/6176]
专题	昆明动物研究所_分子进化基因组学
推荐引用方式 GB/T 7714	吴春花. 兔属和盘羊属的分子进化研究[D]. 北京. 中国科学院研究生院. 2005.

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