The Himalayas as a directional barrier to gene flow
The Himalayas as a directional barrier to gene flow
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DOI：
10.1086/516757
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发表时间：
2007-05-01
影响因子：
9.8
通讯作者：
Herrera, Rene J.
中科院分区：
文献类型：
--
作者：
Gayden, Tenzin;Cadenas, Alicia M.;Herrera, Rene J.
高分辨率Y染色体单倍群分析结合Y短串联重复序列（STR）单倍型被用于（1）调查来自尼泊尔的三个群体的遗传亲和力-包括尼瓦尔，塔芒，来自国际化大都市加德满都的人们（后来称为“加德满都”）-以及来自西藏的收藏品和（2）评估喜马拉雅山脉是否代表了青藏高原和南亚次大陆之间基因流动的地理障碍。研究结果表明，藏人和尼泊尔人部分是来自东北亚的藏缅语群体的后裔。所有四个种群都主要由单倍群O3 a5-M134衍生的染色体代表，其基于Y-STR的年龄（+/- SE）估计为一千年前的8.1 +/- 2.9（KYA），比其东南亚同行更近。两个地区之间最显著的差异反映在西藏的单倍群D和尼泊尔的R的相反的高频分布上。除了塔芒，无论是尼瓦尔和加德满都表现出相当大的相似性，印度Y单倍群分布，特别是在其单倍群R和H的组成。这些结果表明，基因流从印度次大陆的情况下，单倍型群R，从欧亚大陆以及，一个结论，也支持的混合物分析。相比之下，单倍群D在尼泊尔完全不存在，但它占西藏Y染色体基因库的50.6%。合并分析表明，单倍群D衍生物（即西藏的D1-M15和D3-P47）的扩展涉及两个不同的人口统计事件（分别是KYA），这些事件比日本常见的D2-M55代表的5.1 +/- 1.8 11.3 +/- 3.7事件更近。相对于尼泊尔，西藏单倍群J和R谱系的低频率也与来自次大陆的限制性基因流一致。然而，单倍群O3 a5-M134代表在尼泊尔的存在表明，喜马拉雅山已经渗透到从东部传播。这些遗传模式表明，这科迪勒拉一直是一个有偏见的双向障碍。
High-resolution Y-chromosome haplogroup analyses coupled with Y - short tandem repeat (STR) haplotypes were used to ( 1) investigate the genetic affinities of three populations from Nepal - including Newar, Tamang, and people from cosmopolitan Kathmandu ( referred to as "Kathmandu" subsequently) - as well as a collection from Tibet and ( 2) evaluate whether the Himalayan mountain range represents a geographic barrier for gene flow between the Tibetan plateau and the South Asian subcontinent. The results suggest that the Tibetans and Nepalese are in part descendants of Tibeto-Burman - speaking groups originating from Northeast Asia. All four populations are represented predominantly by haplogroup O3a5-M134-derived chromosomes, whose Y-STR-based age ( +/- SE) was estimated at thousand years ago 8.1 +/- 2.9 (KYA), more recent than its Southeast Asian counterpart. The most pronounced difference between the two regions is reflected in the opposing high-frequency distributions of haplogroups D in Tibet and R in Nepal. With the exception of Tamang, both Newar and Kathmandu exhibit considerable similarities to the Indian Y-haplogroup distribution, particularly in their haplogroup R and H composition. These results indicate gene flow from the Indian subcontinent and, in the case of haplogroup R, from Eurasia as well, a conclusion that is also supported by the admixture analysis. In contrast, whereas haplogroup D is completely absent in Nepal, it accounts for 50.6% of the Tibetan Y- chromosome gene pool. Coalescent analyses suggest that the expansion of haplogroup D derivatives - namely, D1-M15 and D3-P47 in Tibet involved two different demographic events ( and KYA, respectively) that are more recent than those 5.1 +/- 1.8 11.3 +/- 3.7 of D2-M55 representatives common in Japan. Low frequencies, relative to Nepal, of haplogroup J and R lineages in Tibet are also consistent with restricted gene flow from the subcontinent. Yet the presence of haplogroup O3a5-M134 representatives in Nepal indicates that the Himalayas have been permeable to dispersals from the east. These genetic patterns suggest that this cordillera has been a biased bidirectional barrier.