【作者】 郭丽；

【导师】 杨光；

【作者基本信息】 南京师范大学 ， 生物化学与分子生物学， 2006， 硕士

【摘要】 本论文共包括三个部分： 1．综述近年来中国鲸豚类的保护遗传学研究进展。 2．通过分析345bp的江豚（Neophocaena phocaenoides）线粒体DNA（mitochondrial DNA，mtDNA）控制区（control region或d-loop）序列，分析了北太平洋中国和日本水域江豚的遗传多样性，种群遗传结构以及其系统地理格局。总体上中日水域江豚种群的遗传多样性水平（π=0.44％，h=0.79±0.01）相当低，但不同种群的遗传多样性水平有较大的差异。分子变异分析（AMOVA）提示不同种群之间有很高水平的种群遗传结构(φ_ST=0.61，p＜0.001；F_ST=0.52，p＜0.001)。18个单元型中有11个仅仅出现在一个种群中，其余则为2个以上的种群所共享，但没有发现一个单元型是所有种群所共享的，提示在全新世最后一次冰期江豚发生了多次的种群扩散事件。然而，并没有发现北太平洋中日水域的江豚种群具有明显的系统地理格局。系统重建发生和中接网络（median-joining network）分析均未能把来自不同地理种群或者不同水域的单元型区分为独立的进化枝。较低的遗传多样性水平和较高的种群遗传结构表明在江豚的种群历史中存在随机遗传漂变、瓶颈效应以及创立者效应，并在一定程度上减少或者限制了基因流的发生。此外，还讨论了江豚，特别是长江江豚的保护管理对策。 3．通过420bp的mtDNA控制区序列，对中国水域的江豚种群1990年以前和1990年以后的遗传多样性变化进行分析。结果发现两两种群之间的种群分化程度有显著增加的趋势(1990年前：φ_ST=0.01，p＜0.18，F_ST=0.02，p＜0.001；1990年后：φ_ST=0.35，p＜0.001；F_ST=0.20，p＜0.001)。与此相对应地是，除了南海种群的遗传多样性出现了一定程度地降低外，其它种群的遗传多样性并没有这样的变化趋势。更多还原

【Abstract】 This thesis includes three chapters:1. Some advances in the studies of cetaceans in Chinese waters were reviewed.2. Three hundred and forty-five base pairs （bp） of the mitochondrial DNA （mtDNA） control region were sequenced to analyze the genetic diversity, population structure and history, and phylogeography of finless porpoises （Neophocaena phocaenoides） in Chinese and Japanese waters of the North Pacific. Nucleotide and haplotype diversities were 0.44% and 0.79±0.01 for Chinese and Japanese waters, respectively, but varied significantly among populations. Analysis of molecular variance （AMOVA） showed a high level of genetic structure between populations (Φ_ST=0.61, p<0.001; F_ST=0.52, p<0.001). Eleven of 18 haplotypes were restricted to a single population, common haplotypes were found in two to four populations but no haplotype was found throughout Sino-Japanese waters, suggesting multiple colonization events followed by limited gene flow. The inferred age of demographic expansion was from the end stage of the last ice age to the Holocene. No obvious phylogeographic pattern was revealed, including between saline and fresh water populations. A low level of genetic diversity for each population and high among-population differentiation in haplotype frequency were revealed, which suggest a role for random genetic drift, recent demographic bottlenecks and reduced or limited gene flow in these populations. Some conservation considerations, with special reference to the unique Yangtze更多还原