Genetics, History, and Ethnicity in Daghestan

这是一项建议：(1)开发新的方法来分析种群内部和种群之间的基因分布，并将其与种群历史和关系联系起来；(2)对来自达吉斯坦不同族群的大量DNA进行分类；(3)使用这些遗传数据来研究达吉斯坦地区人民的历史和关系。研究种群历史的遗传方法由于无法将小种群规模的影响与种群遗传隔离分离开来而受到损害。两个分开的种群以与时间除以种群规模成正比的速度积累差异，而且无法知道种群规模，这就要求研究人员假设所有被研究的种群规模都是相等的。这是一个不可接受的假设。大量高度多样化标记的新可用性将允许在群体之间的遗传距离之外单独估计相对群体有效大小，然后使用有效大小估计值来缩放距离。研究人员将在大约400份来自巴基斯坦的样本中分型60个短串联重复标记和几百个Alu标记位点。短串联重复序列没有确定偏差，这种偏差模糊了从经典标记和单核苷酸多态性确定的人类多样性的全球模式。Alu插入具有这样的特性，即基因座上的祖先状态，即缺少标记，总是已知的。这一特性将用于解开古老种群与近代种群的遗传隔离。

This is a proposal to (1) develop new methods for analyzing gene distributions within and between populations and relating these to population history and relationships, (2) type a large collection of DNA from different ethnic groups from Daghestan, and (3) use these genetic data to study history and relationships of the peoples of the Daghestan region. Genetic methods for studying population history have been compromised by the inability to separate effects of small population size from population genetic isolation. Two populations that separate accumulate differences at a rate proportional to time divided by population size, and the inability to know population size has required researchers to assume equal population sizes for all populations studied. This is not an acceptable assumption. The new availability of large numbers of highly diverse markers will allow the estimation of relative population effective sizes separately from genetic distances among populations, then use the effective size estimates to scale distances. The investigators will type 60 short tandem repeat markers and several hundred Alu marker loci in approximately 400 samples from Daghestan. Short tandem repeats are free from the ascertainment bias that has obscured global patterns of human diversity ascertained from classical markers and single nucleotide polymorphisms. Alu insertions enjoy the property that the ancestral state at the locus, absence of the marker, is always known. This property will be used to disentangle old from recent genetic isolation of populations..