【摘要】 目的:提出基因频率矩阵的图论主坐标分析方法,探讨该法在人类群体遗传结构研究中的应用。方法:从分析基因频率矩阵的结构特征入手,将主坐标分析与图论中的最小生成树有机结合,构建人类群体遗传结构的图论主坐标模型,并以中国26个汉族人群HLA-A位点遗传结构分析为例,验证图论主坐标分析的科学性和适用性。结果:图论主坐标分析的基本步骤可概括为:①对中心化基因频率矩阵进行主坐标分析;②按图论原理求过m维空间n个点的最小生成树;③利用求“颈”法分割最小生成树;④将最小生成树整合到二维主坐标散点图中构建图论主坐标分类图。根据此步骤,对中国26个汉族人群HLA-A位点遗传结构进行了图论主坐标分析,分析结果符合中华民族源与流的客观规律。结论:图论主坐标分类图既可显示各群体的遗传结构特性,又可利用最小生成树的连接关系揭示各群体间的内在联系;图论主坐标分析是分析人类群体遗传结构的一种理想方法。更多还原

【Abstract】 Objective: To present the methodology of graph theory principle coordinates analysis and explore its applicability for studying human population genetic structure. Methods: Based on the structure of gene frequency matrix, the model of graph theory principle coordinates analysis by using the method of principle coordinates analysis with the minimal spanning tree of graph theory was set up. As an example, the genetic structure of HLA-A locus in 26 Han populations was analyzed by using graph theory principle coordinates analysis, to show its rationality for studying human population genetic structure. Results: The step of graph theory principle coordinates analysis can be summarized as follows: (a) carry out principle coordinates analysis to the gene frequency covariance matrix; (b)calculate the minimal spanning tree, which passed the n points in m dimensions space; (c) decompose the minimal spanning tree into several parts based on the method of necks found; (d) set up the graph theory principal coordinates classification graph in the principal coordinates classification scallergram. According to these steps, the genetic structure of HLA-A locus in 26 Han populations was analyzed, which indicated that the results accorded with the population genetic mechanism of Chinese Han population. Conclusion: The graph theory principal coordinates classification scallergram can show not only the genetic structure of populations, but also the intrinsic relationship among the populations. The graph theory principle coordinates analysis is an ideality method for studying the human population genetic structure.更多还原