Olaisen B, Bekkemoen M, Hoff-Olsen P, Gill P
Institute of Forensic Medicine, University of Oslo.
EXS. 1993;67:63-9. doi: 10.1007/978-3-0348-8583-6_6.
Seven hypervariable VNTR loci have been studied in about 1200 parent/child pairs about equally divided between the sexes. Mutations were observed with all seven probes, the total number being 71. Fourty-four of these involved increased fragment length. Gains in fragment length were on average larger than losses. These findings indicate that mutation might be a basis for evolutionary expansion of VNTR fragment length. For five probes YNH24 (D2S44), MS31 (D7S21), g3 (D7S22), MS43A (D12S11), and CMM101 (D14S13), mutation rates were relatively low (less than 1%) with no obvious sex difference. MS1 (D1S7) mutation frequencies were substantially higher, with a tendency towards a higher paternal than maternal mutation rate (5.4% and 2.0%, respectively). The probe B6.7 (provisionally assigned to chromosome 20) exhibits about five times higher paternal than maternal mutation rates. The mutation rate of 7.6% in paternal chromosomes is among the highest reported in any VNTR locus. These findings could indicate that while low-mutant VNTRs might reflect meiotic crossover, mutation events in high-mutant loci could more often be caused by other mechanisms during cell division.
在约1200对亲子对中研究了7个高变VNTR基因座，这些亲子对在性别上大致均等分布。使用所有7种探针均观察到了突变，总数为71个。其中44个涉及片段长度增加。片段长度的增加平均大于减少。这些发现表明突变可能是VNTR片段长度进化扩展的基础。对于5种探针YNH24（D2S44）、MS31（D7S21）、g3（D7S22）、MS43A（D12S11）和CMM101（D14S13），突变率相对较低（小于1%），且无明显性别差异。MS1（D1S7）的突变频率显著更高，父系突变率高于母系突变率（分别为5.4%和2.0%）。探针B6.7（暂定为20号染色体）的父系突变率比母系突变率高约5倍。父系染色体中7.6%的突变率是在任何VNTR基因座中报道的最高突变率之一。这些发现可能表明，低突变的VNTR可能反映减数分裂交叉，而高突变基因座中的突变事件可能更多是由细胞分裂期间的其他机制引起的。
