【作者】 赵凯；

【导师】 杨公社； 何舜平；

【作者基本信息】 西北农林科技大学 ， 动物遗传育种与繁殖， 2005， 博士

【摘要】 青海湖及其邻近的黄河和柴达木水系分布着裂腹鱼亚科的8 个特有种和亚种,它们的系统发育模式和种群进化关系受到了越来越多的关注。裸鲤属和裸裂尻鱼属在这一地区有广泛的分布,它们的河流栖息环境为生物地理学研究提供了理想的模式。本文以线粒体DNA(mtDNA)为标记,对来自青海湖、黄河和柴达木水系特有的青海湖裸鲤(青海湖裸鲤指名亚种和青海湖裸鲤甘子河亚种)、花斑裸鲤、斜口裸鲤、黄河裸裂尻鱼、柴达木裸裂尻鱼和极边扁咽齿鱼Cyt b 基因全序列和控制区D-loop 序列进行了测定分析。通过分子系统学研究,拟阐明特有裸鲤鱼、裸裂尻鱼和扁咽齿鱼种间及种内的系统发育模式和分类关系。用生物地理学方法,探讨青海湖裸鲤的起源和演化历史,分析青海湖裸鲤、花斑裸鲤和黄河裸裂尻鱼地理分布格局的形成和水系变迁,以及青藏高原的隆升对物种形成的影响,为青海湖的形成和黄河溯源的历史提供生物学证据。本项目具有重要的系统学、地理生物学和保护生物学意义, 同时为阐述青藏高原裂腹鱼类的系统进化规律积累有价值的资料。通过本研究,我们们得出了以下结论: 1.在一致的系统进化树上,裸鲤属的3 个物种(青海湖裸鲤、花斑裸鲤和斜口裸鲤)并未形成三个独立的单系群,而是分为三个谱系:谱系A 包括青海湖裸鲤、斜口裸鲤和黄河花斑裸鲤的一部分,黄河花斑裸鲤的另一部分组成谱系B,它们形成姐妹群关系;谱系C 则由来自柴达木盆地格尔木河的花斑裸鲤形成单系群;极边扁咽齿鱼位于系统树的基部,形成特有的单系群。AMOVA 分析显示,大部分的遗传变异来自于谱系间,提出该地区裸鲤属鱼类存在3 个多样化谱系。2.青海湖裸鲤与其甘子河亚种在mtDNA 水平没有形成分化,不支持青海湖裸鲤为多型种,也不支持斜口裸鲤作为独立的种或作为花斑裸鲤的一个亚种。柴达木盆地格尔木河的花斑裸鲤形成单系群,与黄河花斑裸鲤间非常高的遗传分歧表明。基因交流长期被阻断,暗示生态隔离可能已经使柴达木裸鲤独立进化成相当于不同的种。3.黄河花斑裸鲤群体内的遗传分化表明,黄河上游峡谷对裸鲤的基因交流有一定的限制。黄河花斑裸鲤的另一谱系(谱系B)很可能与黄河的溯源历史有关。4.网络分析显示,黄河花斑裸鲤存在多个母系来源,它们可能是黄河溯源过程中更多还原

【Abstract】 Lake Qinghai and adjacent Yellow River and Qaidam drainage include 7 unique species and 1 subspecies of Schizothoracinae. Molecular phylogenetics of them have recently received much attention. Among them, 4 species (G. przewalskii, G. eckloni, G. scolistomus and Schizopygopsis pylzovi) of Gymnocypris and Schizopygopsis are widely distributed in those areas, and these fishes dwelling in the isolated river habitats provide an ideal model for phylogeographical studies. In this study, the complete mtDNA cytochrome b gene(1141bp)and D-loop control region (594 bp) sequences were sequenced for analysesing the genetic structure and phylogenetic relationships of G. przewalskii, G. eckloni, G. scolistomus, Schizopygopsis pylzovi and Platypharodon extremus from Lake Qinghai, Yellow River and Basin Qaidam, respectively. we aimed to provide a diversification of the mtDNA lineages hypothesis for the schizothoracine fishes in this area, and combining the geological data clarified the relation of origin between G. przewalskii and G. eckloni, and the effect of the uplift of Qinghai-Tibet Plateau on speciation, this will also provide biological evidence for the forming of the Lake Qinghai and the history of headward erosion for Yellow River. 1. Congruent phylogenies were obtained indicating that the samples collected from the same species did not form monophyletic groups, but they grouped three highly divergent lineages (A, B and C). Among them, lineage A contained all G. przewalskii, G. scolistomus and a part of G. eckloni from Yellow River, lineage B was only composed of other G. eckloni from Yellow River, and lineage C formed a monophyly by G. eckloni from Basin Qaidam. Analysis of molecular variance (AMOVA) indicated that most of the genetic variation was detected among the three mtDNA lineages. and suggesting there were three diversiform lingeages for Gymnocypris in this region. 2. Our mtDNA data did not support that G. przewalskii was a polytypic species, and neither G. scolistomus was an independent species nor a subspecies of G. eckloni. The G. eckloni from Basin Qaidam was a monophyletic group (lineage C) with high bootstrap value, and long-term interruption of gene flow was evidenced by high Fst values, suggesting thepopulation of G. eckloni from Basin Qaidam might have be a different species. 3. The divergent mtDNA lineages of G. eckloni from Yellow River suggested a part of the gene flow among the populations was restricted by several gorges on the upper reaches of Yellow River. The lineage B of G. eckloni might relate to its history of headward erosion of Yellow River. 4. The result of network analysis showed the G. eckloni from Yellow River had multiple maternal origins, they might be the genetic character of the ancestor from the endemic schizothoracinae fishes, which incorporated in the course of the headward erosion by Yellow River reach. 5. In network structure analysis, a founder haplotype of unique to Yellow River linked all specimens form G. przewalskii suggesting that G. przewalskii might originate from one lineages of G.eckloni of Yellow River. The G. przewalskii ganzihonensis coming from G. przewalskii was supported, but genetic divergence between them has been not largely formed. 6. The test of selective neutrality showed that lineages diversification of G. przewalskii took place about 0.14MaBP years ago, it was near the times that the “Gonghe Movement”event of Qinghai-Tibetan Plateau to cause the separation of Lake Qinghai from the upper reaches of Yellow River. So that “Gonghe Movement”event in the late Pleistocene might well explain to shape the evolutionary pattern of G. przewalskii and G. eckloni. A local expansion of the G. eckloni from Yellow River about 0.072MaBP might happen in the course of headward erosion of Yellow River. The population expansion was tested also within G. eckloni from Basin Qaidam about 0.036MaBP, it might be related to the very dry during late Pleistocene in Basin Qaidam. This result was also supported by the mismatch analysis. 7. All Gymnocypris populations exhibited a low nucleotide diversity, especially the Gymnocypris populations from Basin Qaidam showed a very low nucleotide diversity suggesting that they might have experienced a very severe bottleneck. This result is congruent with a fact that the global climate became extremely worsen to cause extinction of some species in the later Pleistocene. Our result suggested a high priority in conservation programs for Gymnocypris population of Basin Qaidam. 8. Correlation test between the rakers variety of the population of Gymnocypris and genetic distances showed a non-significant correlation, and suggested that the rakers and oblique mouth cleft might have little significance in the phylogeny of the Gymnocypris fishes. 9. The Schizopygopsis from Lake Tuosuo of Basin Qaidam did not form monophyleticgroup. Our results supported the morphological classification that merged the Schizopygopsis kessleri into Schizopygopsis pylzovi. The divergent time of the Schizopygopsis Pylzovi of Yellow River and Lake Tuosuo was about 0.07MaBP ago in the late Pleistocene.更多还原