柬埔寨人群的起源和史前迁徙的遗传学研究
文献类型：学位论文
| 作者 | 张晓明 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 宿兵 |
| 关键词 | 柬埔寨人群 南亚语系 起源与迁徙 mtDNA新支系 Y-DNA O2a-M95支系 |
| 其他题名 | Genetic Study of Origin and Prehistoric Migration of Cambodian Populations |
| 学位专业 | 遗传学 |
| 中文摘要 | 亚洲大陆的南部分布着使用多种复杂语系语言、民俗文化类型丰富多彩和体质外貌多样化的众多民族。我们之前对东亚人群的研究及其他相关的研究认为，现代人的祖先走出非洲后经“南线”的海岸线迁徙，约6万年前到达了亚洲南部的东南亚大陆（MSEA），随后部分人群向北迁徙，约3-4万年前进入东亚南部，而另一部分人群则快速向南迁徙到达东南亚诸岛（ISEA），太平洋诸岛和澳洲等广泛地区。然而，目前对这一迁徙过程中具有重要地位的MSEA人群的遗传学研究却比较少，特别是一些关键的沿海区域，如柬埔寨，相关人群的起源和迁徙历史研究基本处于空白状态。 柬埔寨位于MSEA最南部的沿海区域，该地区是现代人“南线”迁徙到达MSEA之后向南向北迁徙的“岔路口”。因此，柬埔寨人群在探讨整个东南亚、东亚、太平洋群岛和澳洲人群的进化历史中具有重要的研究意义。为此，本研究对柬埔寨东北部山区多个土著民族人群进行了系统的遗传学筛查。 首先，我们对柬埔寨东北部14个土著民族群体共1,054份样本进行了系统的mtDNA分析，发现了8个新的mtDNA支系/亚支系。它们的最近共祖时间（TMRCA）都非常古老，特别是新根部支系的TMRCA在约5.5-6.8万年之间，与之前我们提出的现代人的祖先最早定居于亚洲南部的时间非常吻合；另外，柬埔寨人群的主要mtDNA支系在本地的遗传多样性和频率都高于周边人群，柬埔寨可能是这些支系的扩散中心；主成分分析观察到柬埔寨人群与来自印度次大陆、安达曼群岛、澳洲（土著）和马达加斯加岛人群的关系较为密切；这些结果一致证实柬埔寨人群是比较古老的人群。 其次，我们对这些柬埔寨人群中的365份男性样本进行了Y-DNA系统分析，发现O2a-M95支系是柬埔寨人群的主要父系支系（约占70%），该支系在柬埔寨人群中有中等水平的遗传多样性和比较古老的TMRCA (约3万年前)；从我们的综合分析和目前的多项研究来看，我们推测O2a-M95支系很有可能在旧石器时期起源于东亚南部的沿海地区，其发源人群可能是该地区的侗傣语系等人群。所以，与母系遗传成分不同，柬埔寨人群的父系主要是从其他地区的人群扩散而来的，并且这种扩散历史伴随着大量的男性人群迁徙、融合甚至取代当地土著男性的过程。另外，我们在柬埔寨人群中还检测到可能分别从中国南方和ISEA人群中扩散而来的两个中低频率支系O3-M122和O1a-M119，以及非常低频的印欧人群和东亚人群常见的支系类型R-M207、C-M130、D1a-N1、J2-M172、K*-M9、Q1-P36.2、F*-M89和N-M231等。所以，柬埔寨人群在历史上经历了性别特异性大融合的过程，其保留了走出非洲后最早到达MSEA定居者的古老母系遗传成分，但是父系遗传成分被后期从中国南方等地区大面积扩散迁徙而来的人群融合取代了。 最后，我们系统探讨了柬埔寨人群主要父系支系O2a-M95的系统发育结构及其起源和扩散历史；以柬埔寨、泰国和中国云南的多个南亚语系人群样本系统分析，将O2a-M95支系更新为了5个下游分枝：O2a1*-M95、O2a1a-F789、O2a1b*-F1252、O2a1b1*-M88和O2a1b1a-F761，其中O2a1a-F789是频率最高的分枝（85.22%）。我们对携带O2a-M95支系的亚洲大陆127个人群的系统分析，推测该支系在旧石器时期（约2.5-3.5万年前）起源于中国南部的侗傣语系等人群中并向四周快速扩散，大约在新石器早期（约1.5万年前）向西南方向大面积扩散到达了MSEA和印度东北部，随后进一步扩散到了ISEA和印度次大陆的中南部等广泛地区。其中，向西迁徙进入印度次大陆的人群在喜马拉雅山脉的长期地理隔离下发生了较大的分歧，但总体来说各地理人群之间还没有发生明显的分化。O2a-M95支系在广泛的亚洲大陆南部的这种大面积扩散历史可能伴随着多个语系语言间的分化和交融的过程。 |
| 英文摘要 | In southern part of eastern Asia, there are a lot of diversified ethnic groups that can be differentiated by their language, culture and physical appearance. From previous reports, the early settlers from Africa migrated along the “southern route” and reached mainland Southeast Asia (MSEA) ~ 60 thousands ago. Later, some of them migrated northward and entered southern part of East Asia ~ 30-40 thousands ago. Also, there was southward migration island Southeast Asia (ISEA), Oceania and Australia. However, despite their critical role in these peopling histories, the populations in MSEA have rarely been studied for genetic diversity, especially the coastline regions in MSEA, such as Cambodia. The genetic origin and migratary histories of Cambodian populations are yet to be revealed. Located on the southern coast of Indochina Peninsula, Cambodia is the “crossing site” of the “northward” and “southward” migration waves. Thus, Cambodians are important in tracing the origin, and prehistoric peopling in southern part of eastern Asia, Oceania and Australia. In this study, we aim to reveal the comprehensive genetic profiles of Cambodian aborigines. Firstly, we investigated the matrilineal gene pool of 1,054 Cambodians from 14 geographic populations, and we identified 8 novel mtDNA haplogroups, which have very old coalescence ages, ranging from ~55,000 to ~68,000 years; this is congruent with our previous view that the first settlers of modern human reached southern parts of eastern Asia some 60,000 years ago. In addition, most of the common Cambodian haplogroups have the highest diversity among the studied populations, indicating they originated locally in Cambodia before expanding to the surrounding areas during prehistory. Moreover, we observed a relatively close relationship between Cambodians and populations from the Indian subcontinent, Andaman Island, Australia and Madagascar. All of these results suggest that Cambodians are very ancient populations in Asia. Secondly, after systematic analysis of the Y-DNA of 365 male samples from Cambodia, we detected that the most dominant Y-lineage in Cambodians is O2a-M95 (~70%), and it has medium level of haplotype diversity in this region and relatively old TMRCA. From our comprehensive analysis and other previous reports, we postulated that the O2a-M95 lineage originated in coastline regions of southern part of eastern Asia during Palaeolithic period, and the Daic speaking populations are likely the ancestral populations in these regions. Thus, different from their matrilineal gene pool, the major patrilineal component of Cambodians were likely from surrounding populations through massive male population migration, admixture and replacement of the local aboriginal males. Additionally, we also detected low frequency lineages, O3-M122 and O1a-M119, which were originally from the southern part of China and ISEA respectively. We also observed rare lineages (R-M207, C-M130, D1a-N1, J2-M172, K*-M9, Q1-P36.2, F*-M89 and N-M231), which are prevalent in India, Europe and East Asia. Thus, Cambodians have undergone massive sex-biased admixture in history, and they maintained the ancient matrilineal gene pool from the earliest ancestors who firstly settled in MSEA. Howerver, their paternal genetic pool were displaced by massive latter migrators who were from southeast coastline regions of East Asia. Finally, we conducted a systematic analysis of the sub-structure, origin and dispersal patterns of lineage O2a-M95. With many Austro-Asiatic population samples from Cambodia, Thailand and Yunnan province of China, we updated the phylogeny of O2a-M95 by defining 5 sub-branches: O2a1*-M95, O2a1a-F789, O2a1b*-F1252, O2a1b1*-M88 and O2a1b1a-F761, in which the O2a1a-F789 is the most dominant (accounting for 85.22%). In addition, we analysed 127 populations from Asia that harbor the O2a-M95 lineage, and proposed that this lineage may originate in southern parts of eastern Asia among the Daic populations aroun |
| 语种 | 中文 |
| 公开日期 | 2014-07-14 |
| 源URL | [http://159.226.149.42:8088/handle/152453/7954]  |
| 专题 | 昆明动物研究所_比较基因组学 |
| 推荐引用方式 GB/T 7714 | 张晓明. 柬埔寨人群的起源和史前迁徙的遗传学研究[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：昆明动物研究所
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