缅北及周边地区鬣羚和斑羚的物种分化机制

Influenced by the several uplifts of the Qinghai-Tibet Plateau, the northern Myanmar and surrounding areas, joint of the Himalayas and Hengduan Mountains, harbors exceptional levels of flora and fauna, which is unusual and enigmatic among global biodiversity hotspots. Many large mammal species have been discovered or rediscovered since decades. More than half of the species with gorals (Nemorhaedus) and serows (Capricornis)are distributed in these mountainous region. Most of the studies on taxonomy of gorals and serows are based on morphological characteristics, and the conclusions are still debated. The molecular biology research about them is limited. Even in the NCBI database, we could not find any genetic data of these two genera species from the northern Myanmar and adjacent areas. The inconvenient traffic and the frequent wars make it quite difficult to survey and to collect samples in these regions. Working with the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, we conducted several biodiversity survey in northern Myanmar. 12 goral samples and 40 serow samples were identified by DNA-barcoding, among which the mitochondrial genome sequences of 8 goral samples and 5 serow samples were sequenced. With the mitochondrial genome sequences download from GenBank, we constructed phylogenetic trees of 12 species from these two genera. Our preliminary results are different from those of morphologically taxonomic studies, and we proposed Nemorhaedus cranbrooki as independent species. Based on our previous research, in a targeted fields of molecular phylogeny, phylogeography and evolutionary biology, we aimed to assess species delimitation of genus Nemorhaedus and Capricornis in Northern Myanmar and adjacent areas; to reconstruct the phylogenetic tree using the mitogenomic sequences, based on newly molecular data; and to explore and to further reveal the phylogeography and evolutionary history of genus Nemorhaedus and Capricornis.

受青藏高原多次抬升影响，位于喜马拉雅-横断山两大山系交汇处的缅北孕育了极为丰富的大中型哺乳动物，是印缅生物多样性热点地区的重要组成部分。斑羚和鬣羚两个近缘属中有一半以上的物种分布于缅北及周边崎岖山地，数量稀少。针对斑羚和鬣羚分类的研究多以形态学为主，且仍有争议。由于该地区交通不便，战事频仍，野外考察和样本采集都比较困难。我们对来自缅北的8个斑羚和5个鬣羚样本进行线粒体全基因组序列测定，结合GenBank已有序列构建了系统发育树，初步结果与已有的形态学研究存在差异。建议恢复Nemorhaedus cranbrooki为独立有效种。本项目拟以已有的研究积累为线索，对缅北及周边地区分布的斑羚属和鬣羚属物种进行广泛采样，结合形态学、多个核基因与线粒体基因联合开展系统发生学、谱系生物地理学和进化生物学方面的研究，厘清缅北及周边两属的物种多样性，探讨并揭示其物种分化形成模式和历史环境因素。

青藏高原东南缘位于喜马拉雅-横断山两大山系交汇处，紧邻缅甸西北部的掸邦高原，是中国西南山地、喜马拉雅地区和印-缅区3个全球生物多样性热点地区的交汇区域。受青藏高原多次抬升影响，这里成为羊羚类等有蹄类物种多样性最丰富、分类和分布也最混乱的地区。羊羚类动物作为典型的林栖独居动物，生存状态受到生境片段化、森林破碎化、以及人类活动的严重干扰，其种群数量曾一度下降。本项目主要以该地区的羊羚类及同域分布的有蹄类动物为研究对象，利用所获得组学数据进行分子系统发育和生物地理学研究，结合经典形态学比较，厘清青藏高原东南缘羊羚类及同域分布的有蹄类物种多样性现状，为物种保护提供有效分子证据。主要研究结果如下：.基于在缅北地区所获得的和已有的斑羚属Naemorhedus 物种线粒体基因组序列，识别出五个独立有效物种：长尾斑羚N. caudatus、喜马拉雅斑羚N. goral、缅甸斑羚N. evansi、赤斑羚N. baileyi和克兰布鲁克斑羚N. cranbrooki。其中，克兰布鲁克斑羚和赤斑羚是不同的物种，而不是同物异名；缅甸斑羚分布向北延伸到中国西南部。分子钟估算表明，斑羚的物种形成与上新世早期到更新世青藏高原和横断山区的隆升事件密切相关。.在青海南部林区获得斑羚的样本被确认为喜马拉雅斑羚，对其已完成全基因组测序、组装和结构和功能的注释。喜马拉雅斑羚共有28条染色体，基因组大小为2.59Gb。基于10个羊亚科物种基因组的系统发育树和PAML MCMCtree分子年代测定结果显示，斑羚和羚牛Budorcas taxicolor关系最近，并与麝牛Ovibos moschatus构成单系群，在约830万年前麝牛与斑羚和羚牛的祖先发生分化，而斑羚则在约760万年前与羚牛祖先分离。需要更多基因组数据构建高置信度的系统发育关系以阐明青藏高原东南缘羊羚类物种起源、扩散、进化和物种形成机制。.同域分布的麂属Muntiacus物种，特别是贡山麂M. gongshanensis的分类地位长期存在争议。基于线粒体基因组的系统发育结果支持贡山麂为独立有效种，并提供了其在中国西南部（云南西部，西藏东南部）、缅甸北部和印度东北部均有贡山麂分布的分子证据。