Alonso S, Castro A, Fernández-Fernández I, de Pancorbo M M
Department of Cell Biology and Morphological Sciences, School of Medicine and Dentistry, Universidad del País Vasco, Vizcaya, Spain.
Am J Hum Genet. 1997 Feb;60(2):417-25.
Short VNTR alleles that go undetected after conventional Southern blot hybridization may constitute an alternative explanation for the heterozygosity deficiency observed at some minisatellite loci. To examine this hypothesis, we have employed a screening procedure based on PCR amplification of those individuals classified as homozygotes in our databases for the loci D1S7, D7S21, and D12S11. The results obtained indicate that the frequency of these short alleles is related to the heterozygosity deficiency observed. For the most polymorphic locus, D1S7, approximately 60% of those individuals previously classified as homozygotes were in fact heterozygotes for a short allele. After the inclusion of these new alleles, the agreement between observed and expected heterozygosity, along with other statistical tests employed, provide additional evidence for lack of population substructuring. Comparisons of allele frequency distributions reveal greater differences between racial groups than between closely related populations.
传统Southern印迹杂交后未检测到的短串联重复序列（VNTR）等位基因可能是某些微卫星位点观察到杂合性不足的另一种解释。为检验这一假设，我们采用了一种筛选程序，该程序基于对我们数据库中D1S7、D7S21和D12S11位点分类为纯合子的个体进行PCR扩增。获得的结果表明，这些短等位基因的频率与观察到的杂合性不足有关。对于多态性最高的位点D1S7，之前分类为纯合子的个体中约60%实际上是短等位基因的杂合子。纳入这些新等位基因后，观察到的杂合性与预期杂合性之间的一致性，以及所采用的其他统计检验，为缺乏群体亚结构提供了额外证据。等位基因频率分布的比较显示，种族群体之间的差异大于亲缘关系密切的群体之间的差异。
