Y染色体揭示的早期人类进入东亚和东亚人群特征形成过程

【作者】 蔡晓云；

【导师】 金力；

【作者基本信息】 复旦大学 ， 人类生物学， 2009， 博士

【摘要】 人类自诞生以来,从未停止过对自身的探索,现代人类的起源问题,也总能引起人们的探索热情和无休止的争论。在分子人类学的研究中,对基因组研究的深入,为人类进化的探索注入了新的活力。尤其是对人类Y染色体非重组区上突变位点的研究推动了遗传物质在进化领域的研究,得以父系遗传结构角度构建系统发生树,来分析群体中的各种结构关系,从而阐明世界各地不同人群之间的系统演化关系,并以此来与各种其它领域的人类学研究结果综合判断群体的系统发生历史。尽管东亚人群的起源仍存在争议,对东亚及周边人群的分子人类学研究发现,绝大多数东亚的Y染色体世系是来源于东南亚的。然而,对于被认为是东亚人祖先群体的东南亚人群的研究,却是寥寥。因此,对从东南亚到东亚迁徙的设想及其对东亚人群遗传结构形成的影响需要进一步的了解。在该研究中对主要分布在东南亚并延伸至东亚的孟高棉族群和苗瑶族群的47个人群的1,652个个体的Y染色体数据进行了分析。几乎仅在这两个族群中分布的单倍群03a3b-M7显示出该两大组群深厚的联系。根据STR绘制的单倍群03a3b-M7网络结构图显示出很明显的分层结构,孟高棉族群个体的单倍型位于中心/入口处,苗瑶和藏缅族群个体的单倍型分布在远离入口的地方。此外,尽管单倍群03a3c1-M117不像03a3b那样特殊,但也显示出同03a3b-M7类似的网络结构。这表明,携带该两种单倍群的早期现代人从东南亚向东亚迁徙的过程是缓慢而平稳的,伴随着很多小型的瓶颈效应,因而导致了这种从东南亚到东亚的单向扩散格局。通过时间估算,单倍群03a3b-M7的年龄约为15,300年,而03a3c1-M117的年龄则要更老在20,000年左右。他们都见证了苗瑶世系的祖先从孟高棉祖先族群中分化出来,并且单向往北迁徙到东亚。而中南半岛侗台族群的起源,则是我们研究中关注的另一个问题。包含泰和佬人民的侗台族群在中南半岛上人口为数最多。侗台族群不像孟高棉族群那样被认为是中南半岛的土著,而是从北面迁徙而来。然而它的文化和人群起源尚有争议。在我们的研究中,主要通过比较中南半岛侗台族群和中国侗台以及孟高棉族群的Y染色体多样性,以期揭示中南半岛侗台族群的起源。我们一共检测了来自老挝人民民族共和国九个侗台族群Y染色体非重组区域的二十个单核苷酸多态位点(SNPs)和十七个短片段重复多态(STRs)。主成分分析和网络结构图的构建都显示,中南半岛侗台族群中很少的Y染色体世系(仅有单倍群01a)是来自中国侗台族群的,而绝大多数父系世系都是源自孟高棉族群。因此我们得出这样的结论,中国侗台族群中有限的一小部分人将侗台文化从中国带到了中南半岛,随后同化了很多土著的孟高棉人。更多还原

【Abstract】 Since the naissance of humankind,there is endless work to probe into the selves of their own,especially the origin of modern human which can always arouse the enthusiasm of exploration and incessant controversy.In the studies of molecular anthropology,in-depth study of genome injected new vitality into the search on the evolution of human beings:the evolutionary study of genes was impelled by the research on the variations of the non-recombining portion of the Y-chromosome (NRY),thus the phylogenetic tree can be constructed from the genetic aspects of paternal structure to analyze the structures and relationships among populations, elucidating the phylogenetic relationships between the populations all over the world, which is used to reconstruct the phylogenesis of populations combined with the results from other anthropotogic fields.Though the origin of East Asians is still controversial,a rapid accumulation of molecular anthropological studies of the populations in and around East Asia resulted in the discovery that most of the Y chromosome lineages of East Asians came from Southeast Asia.However.little investigation has been conducted on the Southeast Asian populations which are supposedly the ancestral populations of East Asians. Therefore,the supposed migrations from Southeast Asia into East Asia and their roles in shaping genetic structure of East Asian populations are yet to be understood.Here we present the Y chromosome data of 1,652 individuals from 47 populations of Mon-Khmer(MK) and Hmong-Mien(HM),which distribute primarily across Southeast Asia and extend into East Asia.Haplogroup O3a3b-M7 which can only be found in these two groups indicates a strong tie between them.The short tandem repeat(STR) network of O3a3b-M7 displayed a hierarchical expansion structure,with the Mon-Khmer haplotypes in the center/entrance,the Hmong-Mien and the Tibeto-Burman haplotypes distributed further away from the entrance.Moreover, haplogroup O3a3c1-M117 shows the similar network structure as O3a3b-M7 though the distribution of O3a3c1 is not as specific as O3a3b.These patterns indicate a unidirectional diffusion from Southeast Asia into East Asia,which might have resulted from the slow and even migration of early modern humans’ carrying these two haplogroups from Southeast Asia to East Asia by many small bottle-neck effects. The age of O3a3b-M7 was estimated to be approximately 15,300 years while that of O3a3c1-M117 is a bit older around 20,000 years,followed by the emergence of the ancestors of HM lineages out of MK and the unidirectional northward migrations into East Asia.The origin of Peninsular Daic is another focus of attention for us to study.The Daic ethnic group including Thai and Lao people has the largest population in the Indo-China Peninsula.Not like the Mon-Khmer native to the Peninsula,the Daic populations were considered to be migrants from the north.However,the origin of its cukure and population remains controversial.In this study,we compared the Y chromosome diversity of the Peninsular Daic to those of Chinese Daic and the Mon-Khmer populations to reveal the origin of the Peninsular Daic populations.We typed twenty single nucleotide polymorphisms(SNPs) and seventeen short tandem repeats(STRs) in the non-recombining region of Y chromosomes sampled from nine Daic populations from the Republic of Lao.Principal component analysis and NETWORK construction showed that very few Y lineages(haplogroup O1 a only) of the Peninsular Daic came from the Chinese Daic,but most of the other patrilineal lineages originated in the Mon-Khmer people.Therefore,we demonstrated that the Daic culture may have been carried by finite people from the Daic populations in China to the Indo-China Peninsula and subsequently assimilated many native Mon-Khmer people.更多还原