P-20探针位于DMD基因突变热点区,是DMD基因诊断最常用的多态标记。作者在分析21个DMD家系时,除检测到多态片段Msp I 6.0/3.5kb外,在全部受检者中还发现另一组高频多态位点Msp I 2.2/1.8kb,二组多态联合检出杂合子频率为0.7004,使P-20对DMD的RFLP分析能力提高近一倍。根据缺失类型进一步分析了P-20区的基因图谱。 The P-20 probe is located in the hot spot of the DMD gene mutation and is the most commonly used polymorphic marker for the diagnosis of DMD. In analyzing 21 DMD pedigrees, in addition to detecting Msp I 6.0 / 3.5 kb polymorphic segment, another group of high frequency polymorphism sites Msp I 2.2 / 1.8kb were found in all subjects, more than two groups The combined detection of heterozygote frequency was 0.7004, which made the P-20 nearly double the ability of RFLP analysis of DMD. According to the deletion type further analysis of the P-20 region of the gene map.