消化后片段长度差异等位基因特异性PCR技术--印记SNP rs220028多态性和甲基化模式研究

目的建立一种能同时分析甲基化和单核苷酸多态性(single nucleotide polymorphism，SNP)的新方法。方法以印记SNP rs220028(A／G)为例，基因组DNA经甲基化敏感限制酶消化后用片段长度差异等位基因特异性PCR(fragment length discrepant allele—specific PCR，FLDAS—PCR)分型；用扩增产物酶消化法来排除酶切位点序列变异，证实检出的是甲基化等位基因。结果消化后FLDAS—PCR可选择性检出甲基化等位基因，家系分析表明其来自母亲。等位基因频率A=0．5085．G=0．4915，多态信息含量为0．3749。结论消化后FLDAS—PCR技术可以实现甲基化和SNP的复合分析；印记SNP rs220028在Prader—Willi／Angelman综合征诊断中有潜在意义。

The multiplex analysis of epigenetic markers and genetic markers by post-digestion mutagenically separated PCR

Objective To establish a novel method for the multiplex analysis of the methylation and single nucleotide polymorphism (SNP). Methods The imprinted SNP rs220028 was chosen as a model. Genomic DNA, after being digested with methylation sensitive restriction enzyme, were typed by mutagenically separated PCR (MS-PCR). The polymorphism of restriction site was excluded by PCR-RFLP. Results By post-digestion MS-PCR, the methylated allele was detected selectively, the maternal origin of which was confirmed by pedigree analysis; A=0.5085,G=0.4915,PIC=0.3749. Conclusion The multiplex analysis of methylation markers and SNP can be achieved by post-digestion MS-PCR. The imprinted SNP locus rs220028 is a potentially useful marker in screening Prader-Willi/Angelman syndrome.