Facultad de Medicina, UNAM, Mexico City, México.
J Hum Genet. 2009 Dec;54(12):695-705. doi: 10.1038/jhg.2009.98. Epub 2009 Oct 16.
There are limited data on mitochondrial DNA (mtDNA) variation in the Mexican mestizo population. To examine the genetic diversity and matrilineal ancestry, the full mtDNA hypervariable regions I and II were sequenced in 270 unrelated mestizos from different regions of Mexico. A total of 202 different haplotypes were identified and the haplotype diversity was 0.9945. Amerindian haplotypes predominated in the sample with a proportion of 93.3%, followed by European (6.0%) and African haplotypes (0.7%). The frequency of the Amerindian haplogroups A2, B2, C1 and D1 was 51.1, 17.8, 18.5 and 5.9%, respectively. The frequency of Amerindian haplogroups was higher in the central region than in Mexico City, whereas it was the contrary for European haplogroups. This difference was accounted principally by the high frequency of B2 haplotypes in the central region. The minimum spanning network, the mismatch distribution and Tajima's D neutrality test suggest a population expansion for each Amerindian haplogroup, which could be initiated more recently for haplogroups A2 and D1. The present knowledge combined with other nuclear genetic markers will be essential in future association studies to correct for genetic substructure in mestizo populations.
墨西哥混血人群中线粒体 DNA（mtDNA）变异的相关数据有限。为了研究遗传多样性和母系祖先，我们对来自墨西哥不同地区的 270 名无关混血个体的 mtDNA 高变区 I 和 II 进行了测序。共鉴定出 202 种不同的单倍型，单倍型多样性为 0.9945。样本中以美洲原住民单倍型为主，占比 93.3%，其次是欧洲（6.0%）和非洲单倍型（0.7%）。美洲原住民单倍群 A2、B2、C1 和 D1 的频率分别为 51.1%、17.8%、18.5%和 5.9%。与墨西哥城相比，中部地区的美洲原住民单倍群频率更高，而欧洲单倍群则相反。这种差异主要归因于中部地区 B2 单倍型的高频率。最小生成树网络、错配分布和 Tajima 的 D 中性检验表明，每个美洲原住民单倍群都发生了种群扩张，其中 A2 和 D1 单倍群的扩张可能发生在更近的时期。结合其他核遗传标记的现有知识，对于未来的关联研究纠正混血人群的遗传亚结构至关重要。
