Google

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

 找回密码
 注册
查看: 2725|回复: 4

族群相关SNP研究:Population-specific common SNPs reflect demographic histories

[复制链接]
发表于 2016-8-1 15:25 | 显示全部楼层 |阅读模式
Population-specific common SNPs reflect demographic histories and highlight regions of genomic plasticity with functional relevance
Background                Population differentiation is the result of demographic and evolutionary forces. Whole genome datasets from the 1000 Genomes Project (October 2012) provide an unbiased view of genetic variation across populations from Europe, Asia, Africa and the Americas. Common population-specific SNPs (MAF > 0.05) reflect a deep history and may have important consequences for health and wellbeing. Their interpretation is contextualised by currently available genome data.
              
                Results                The identification of common population-specific (CPS) variants (SNPs and SSV) is influenced by admixture and the sample size under investigation. Nine of the populations in the 1000 Genomes Project (2 African, 2 Asian (including a merged Chinese group) and 5 European) revealed that the African populations (LWK and YRI), followed by the Japanese (JPT) have the highest number of CPS SNPs, in concordance with their histories and given the populations studied. Using two methods, sliding 50-SNP and 5-kb windows, the CPS SNPs showed distinct clustering across large genome segments and little overlap of clusters between populations. iHS enrichment score and the population branch statistic (PBS) analyses suggest that selective sweeps are unlikely to account for the clustering and population specificity. Of interest is the association of clusters close to recombination hotspots. Functional analysis of genes associated with the CPS SNPs revealed over-representation of genes in pathways associated with neuronal development, including axonal guidance signalling and CREB signalling in neurones.
              
                Conclusions                Common population-specific SNPs are non-randomly distributed throughout the genome and are significantly associated with recombination hotspots. Since the variant alleles of most CPS SNPs are the derived allele, they likely arose in the specific population after a split from a common ancestor. Their proximity to genes involved in specific pathways, including neuronal development, suggests evolutionary plasticity of selected genomic regions. Contrary to expectation, selective sweeps did not play a large role in the persistence of population-specific variation. This suggests a stochastic process towards population-specific variation which reflects demographic histories and may have some interesting implications for health and susceptibility to disease.
 楼主| 发表于 2016-8-1 15:34 | 显示全部楼层
本帖最后由 一统浆糊 于 2016-8-1 15:36 编辑

https://static-content.springer. ... _6211_Fig3_HTML.jpg

这篇这本坛讨论过没?
一个问题请教一下。这是飞哥6,说的是各种群独特SNPs的构成,有多少是来源于祖先的(红色部分),多少是分离后自发的(淡蓝色)部分。我的问题是非洲之外的种群祖源SNP的数量怎么会这么多?尤其是中国人,就算算成绝对数量,也是太多了。本来我估计非洲人应该拥有绝大多数的祖源SNP,比如说80%。这里数据显示连一半都不到。

FIN,IBS 是欧洲人,中间是中国跟日本人,后两个是非洲人。
发表于 2016-8-1 16:45 | 显示全部楼层
每个个体保留的祖源SNPs应是差不多的。不会因为你是非洲人就格外开恩。
 楼主| 发表于 2016-8-2 02:10 | 显示全部楼层
对于个体是这样,但是对于群体不同。
如果出非洲的人群只占当时人类的一小部分。如果机会相同,留在非洲的多数人应该有更多的祖源SNP。相应的,就会看到非洲人基因树更深一些。如同性染色体一样。
除非:1。出非洲人群占相当一部分。OR 2。大量基因回流非洲。OR 3。非洲的多样性被消灭了。
发表于 2016-8-2 10:06 | 显示全部楼层
如果比较不同的个体,就会发现不同的出非洲个体保留的祖源SNPs更接近,非洲个体的差异更大。所以从群体上看,非洲人保留的更多。
您需要登录后才可以回帖 登录 | 注册

本版积分规则

小黑屋|手机版|Archiver|人类生物学在线 ( 苏ICP备16053048号 )

GMT+8, 2020-8-10 13:15 , Processed in 0.183866 second(s), 20 queries .

Powered by Discuz! X3.4

© 2001-2017 Comsenz Inc.

快速回复 返回顶部 返回列表