白族群体间的Y染色体和线粒体DNA多态性的分析

从父系和母系基因库水平上，研究不同分布地区白族群体之间的遗传结构的异同，并对其族源以及本民族群体之间的微进化关系进行初步的探讨。利用PCR-RFLP方法对云南白族和湖南白族及云南的傣族、布依族、独龙族、怒族、阿昌族和湖南土家族共8个群体进行14个线粒体多态位点和Y染色体上的13个双等位基因位点进行基因分型。统计单倍型，在SPSS软件上进行主成分分析。结果显示，两个白族群体在Y染色体双等位基因单倍型分布上差异不大，以H6、H8为主要单倍型分布；在线粒体单倍群分布上，两个白族群体则差异显著，单倍群D、B、M8在湖南白族中的分布频率比云南白族高的多，而在云南白族中M^*、G、F的频率则比湖南白族高。对Y染色体单倍型分布频率进行主成分分析表明两个白族群体聚在一起，整体上和其他北方起源的群体聚成一组；而对线粒体的单倍群分布频率分析显示湖南白族接近湖南汉族和土家族，而云南白族则接近云南怒族和阿昌族。两个白族群体在父系遗传结构上相近，表明他们具有共同的父系族源；而母系遗传结构上的差异，可能与历史上迁到湖南的白族先民主要为男性军士，流寓到当地后与汉、土家等民族女子通婚所致。

The Polymorphism of Y Chromosome and mtDNA Distribution Among Two Bai Populations

In the same ethnic group,people residing at different places may have genetic difference.The difference can be the results of migration and admixture events happened in history.To clarify the genetic relationship and micro-evolution of two Bai ethnic populations residing in Yunnan and Hunan province respectively,we investigated their genetic difference from paternal and maternal genealogy with six other ethnic groups as outgroups.Fourteen loci from mtDNA and thirteen loci from Y chromosome were selected for genotyping using PCR-RFLP methods.Result showed that H6 and H8 are the same dominant Y chromosome haplotypes in two Bai groups.However,the distribution of mtDNA haplogroups showed difference between two Bai populations.D,B,M8 are the predominant haplogroups in Hunan Bai ethnic population,whereas M~*,G,F are dominant in Yunnan Bai ethnic population.Principal Component (PC) analysis based on the Y chromosome haplotypes showed that two Bai ethic populations cluster together.It shows a close paternal genetic relationship between two Bai ethnic populations.From the mtDNA PC plot,it is clear that Hunan Bai is close to Hunan Han and Tujia,whereas Yunnan Bai is close to ethnic groups living in Yunnan province.The difference of mtDNA haplogroup distribution in two Bai people may reflect the maternal gene flow between ethnic groups living in Hunan province after the ancestors of Hunan Bai migrated from Yunnan province to Hunan province 800 years ago.