Parra E J, Marcini A, Akey J, Martinson J, Batzer M A, Cooper R, Forrester T, Allison D B, Deka R, Ferrell R E, Shriver M D
Department of Human Genetics, Allegheny University of Health Sciences, Pittsburgh, Pennsylvania, USA.
Am J Hum Genet. 1998 Dec;63(6):1839-51. doi: 10.1086/302148.
We analyzed the European genetic contribution to 10 populations of African descent in the United States (Maywood, Illinois; Detroit; New York; Philadelphia; Pittsburgh; Baltimore; Charleston, South Carolina; New Orleans; and Houston) and in Jamaica, using nine autosomal DNA markers. These markers either are population-specific or show frequency differences >45% between the parental populations and are thus especially informative for admixture. European genetic ancestry ranged from 6.8% (Jamaica) to 22.5% (New Orleans). The unique utility of these markers is reflected in the low variance associated with these admixture estimates (SEM 1.3%-2.7%). We also estimated the male and female European contribution to African Americans, on the basis of informative mtDNA (haplogroups H and L) and Y Alu polymorphic markers. Results indicate a sex-biased gene flow from Europeans, the male contribution being substantially greater than the female contribution. mtDNA haplogroups analysis shows no evidence of a significant maternal Amerindian contribution to any of the 10 populations. We detected significant nonrandom association between two markers located 22 cM apart (FY-null and AT3), most likely due to admixture linkage disequilibrium created in the interbreeding of the two parental populations. The strength of this association and the substantial genetic distance between FY and AT3 emphasize the importance of admixed populations as a useful resource for mapping traits with different prevalence in two parental populations.
我们使用9个常染色体DNA标记，分析了欧洲基因对美国10个非洲裔人群（伊利诺伊州梅伍德市、底特律、纽约、费城、匹兹堡、巴尔的摩、南卡罗来纳州查尔斯顿、新奥尔良和休斯顿）以及牙买加人群的贡献。这些标记要么是特定人群所特有的，要么在亲代人群之间显示出超过45%的频率差异，因此对于混合血统具有特别的信息价值。欧洲基因血统比例从6.8%（牙买加）到22.5%（新奥尔良）不等。这些标记的独特效用体现在与这些混合血统估计值相关的低方差上（标准误为1.3% - 2.7%）。我们还基于信息丰富的线粒体DNA（单倍群H和L）和Y染色体Alu多态性标记，估计了欧洲人对非裔美国人的男性和女性基因贡献。结果表明欧洲人存在性别偏向的基因流动，男性贡献显著大于女性贡献。线粒体DNA单倍群分析表明，没有证据显示美洲印第安人对这10个人群中的任何一个有显著的母系基因贡献。我们检测到位于22厘摩处的两个标记（FY基因无效型和AT3）之间存在显著的非随机关联，这很可能是由于两个亲代人群杂交产生的混合连锁不平衡所致。这种关联的强度以及FY和AT3之间较大的遗传距离，强调了混合人群作为绘制在两个亲代人群中具有不同患病率性状的有用资源的重要性。
