Curtis David, Vine Anna E
Centre for Psychiatry, Queen Mary's School of Medicine and Dentistry, London, UK.
Hum Hered. 2010;69(3):184-92. doi: 10.1159/000289592. Epub 2010 Mar 4.
Yin yang haplotypes differ at every SNP. A previous study provided striking examples of these haplotypes, but claimed that their distribution across the genome could be attributed to chance. When we studied regions of homozygosity (ROHs) we found haplotypes that tended to differ at several SNPs simultaneously but did not subject this to formal testing. Here, we formally assess whether haplotypes from these regions provide evidence for the yin yang effect.
We identified 20 regions where ROHs are common in a sample of European subjects and studied the most frequent haplotypes of SNPs with high minor allele frequency. We calculated the average 'disparity' between all haplotype pairs using a 'disparity score' calculated as 2(d), where d is the number of SNPs at which a pair of haplotypes differ. We also studied these SNPs in HapMap samples.
Overall, there was highly significant evidence for excess haplotype disparity. Three of the HapMap populations with European ancestry also had statistically significant haplotype disparity scores.
Locations where ROHs are frequent harbour long common haplotypes showing surprising disparity. We believe these haplotypes must represent ancient founder effects and could be valuable for elucidating features of a population's history.
阴阳单倍型在每个单核苷酸多态性（SNP）位点都存在差异。此前的一项研究给出了这些单倍型的显著例子，但声称它们在基因组中的分布可能是随机的。当我们研究纯合子区域（ROH）时，发现了一些单倍型，它们往往在多个SNP位点同时存在差异，但未对此进行正式检验。在此，我们正式评估来自这些区域的单倍型是否能为阴阳效应提供证据。
我们在一组欧洲受试者样本中确定了20个ROH常见的区域，并研究了具有高次要等位基因频率的SNP的最常见单倍型。我们使用“差异得分”计算所有单倍型对之间的平均“差异”，差异得分计算为2(d)，其中d是一对单倍型存在差异的SNP位点数量。我们还在国际人类基因组单体型图计划（HapMap）样本中研究了这些SNP。
总体而言，有非常显著的证据表明单倍型差异过大。三个具有欧洲血统的HapMap群体也具有统计学上显著的单倍型差异得分。
ROH频繁出现的区域含有长的常见单倍型，显示出惊人的差异。我们认为这些单倍型必定代表了古老的奠基者效应，对于阐明一个群体的历史特征可能具有重要价值。
