蓝海人类学在线 Ryan WEI's Forum of Anthropology

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发表于 2019-2-13 12:58 | 显示全部楼层 |阅读模式
Analysis of the human Y-chromosome haplogroup Q characterizes ancient population movements in Eurasia and the Americas

Viola Grugni et al.
BMC Biology 2019 17:3
Published: 24 January 2019


Background: Recent genome studies of modern and ancient samples have proposed that Native Americans derive from a subset of the Eurasian gene pool carried to America by an ancestral Beringian population, from which two well-differentiated components originated and subsequently mixed in different proportion during their spread in the Americas. To assess the timing, places of origin and extent of admixture between these components, we performed an analysis of the Y-chromosome haplogroup Q, which is the only Pan-American haplogroup and accounts for virtually all Native American Y chromosomes in Mesoamerica and South America.

Results: Our analyses of 1.5 Mb of 152 Y chromosomes, 34 re-sequenced in this work, support a "coastal and inland routes scenario" for the first entrance of modern humans in North America. We show a major phase of male population growth in the Americas after 15 thousand years ago (kya), followed by a period of constant population size from 8 to 3 kya, after which a secondary sign of growth was registered. The estimated dates of the first expansion in Mesoamerica and the Isthmo-Colombian Area, mainly revealed by haplogroup Q-Z780, suggest an entrance in South America prior to 15 kya. During the global constant population size phase, local South American hints of growth were registered by different Q-M848 sub-clades. These expansion events, which started during the Holocene with the improvement of climatic conditions, can be ascribed to multiple cultural changes rather than a steady population growth and a single cohesive culture diffusion as it occurred in Europe.

Conclusions: We established and dated a detailed haplogroup Q phylogeny that provides new insights into the geographic distribution of its Eurasian and American branches in modern and ancient samples.
 楼主| 发表于 2019-2-13 13:37 | 显示全部楼层
 楼主| 发表于 2019-2-13 13:46 | 显示全部楼层

图 S3(c)

图 S3(c)

Figure S3. Phylogeography of the branches Q-Y1150, Q-M378 and Q-F1096 (panels a, b and c, respectively). Each panel illustrates the phylogenetic relationships of the markers (in different colours) investigated per each branch and their pattern of frequency distribution (complete list of samples in Additional file 8: Table S6). Circles without any number refer to one subject. Larger circles refer to the number of specified subjects. Stars highlighted by a grey shading refer to ancient samples: (1) [74], (2) [75], (3) [76], (4) [28]; their relative dating, when available, is also reported in italics. Dates reported below branches refer to Bayesian estimates of node ages.
 楼主| 发表于 2019-2-13 14:31 | 显示全部楼层
本帖最后由 cpan0256 于 2019-2-13 14:46 编辑

      在文中提到的1.5Mb长的Y染色体序列上,一个来自阿拉斯加州西部的样本与七个被确定是M120的样本共享12个不属于上游F746或旁支B143的SNP,但是这个样本不包含那七个样本所共享的属于M120的另外18个SNP (F750, F1062, F1830, F1843, F1907, F1908, F1966, F2043, F2045, F2864, F2894, F2998, F3010, F3022, F4710, F5184, M265, M346)。见附件1 (Table S1) 和附件3 (Table S3)。

      文章把这个样本所属的分支暂称为preM120。下面是图S2 (附件5) 的一小部分。

Figure S2. Detailed version of the most parsimonious (MP) tree represented in Fig. 1 and estimated ages of the identified sub-haplogroups. Notes: The length of each branch is not proportional to its age estimate. For each branch, the name of the defining marker(s) and the number of mutations are reported. Markers in italics are outside the sequenced fragments and the relative branches are dotted. Nomenclature in blue colour is according to Jota et al. [25] while names in parentheses are according to Poznik et al. [29].
发表于 2019-2-13 15:27 | 显示全部楼层
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