Bouzekri N, Taylor P G, Hammer M F, Jobling M A
CNRS, UPR 8291, Centre d'Immunopathologie et de Genetique Humaine (CIGH), CHU Purpan, 31300 Toulouse, France.
Hum Mol Genet. 1998 Apr;7(4):655-9. doi: 10.1093/hmg/7.4.655.
The Y-specific locus MSY1 is the only known haploid minisatellite, and displays an extremely high degree of structural diversity which can be assayed by minisatellite variant repeat PCR (MVR-PCR). One group of alleles, in an African-specific class of Y chromosomes (haplogroup 8), behaves unusually in the conventional MVR-PCR assay, and sequencing demonstrates that this is because repeat units in these alleles contain an additional base substitution. We have designed a new MVR-PCR system to detect these novel variants, and show firstly that they are confined to the haplogroup 8 chromosomes, and secondly that the base substitution has spread through these arrays without the elimination of existing repeat variants. The sharing of a particular base substitution between otherwise distinct repeat types in these alleles represents evidence of a remarkable mutation process in their evolutionary history, in which the variant base must have been spread by a biased repair mechanism operating in very small patches within heteroduplexes.
Y 特异性位点 MSY1 是唯一已知的单倍体微卫星，表现出极高程度的结构多样性，可通过微卫星变异重复 PCR（MVR-PCR）进行检测。在一组非洲特异性 Y 染色体类别（单倍群 8）中的等位基因，在传统的 MVR-PCR 检测中表现异常，测序表明这是因为这些等位基因中的重复单元包含额外的碱基替换。我们设计了一种新的 MVR-PCR 系统来检测这些新变体，首先表明它们仅限于单倍群 8 染色体，其次表明碱基替换已在这些阵列中传播，而没有消除现有的重复变体。这些等位基因中原本不同的重复类型之间共享特定的碱基替换，这表明在它们的进化历史中存在一个显著的突变过程，其中变异碱基必定是通过在异源双链体中非常小的片段内起作用的偏向修复机制传播的。
