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目的探讨O6-甲基鸟嘌呤-DNA-甲基转移酶(MGMT)基因遗传多态性位点在广东省高本底地区(HBRA)汉族人群中的分布特征。方法采用单纯随机抽样方法,选择60名广东省HBRA汉族人群,获取其周围血基因组DNA,通过聚合酶链式反应(PCR)扩增获得MGMT基因5’侧翼区和第一编码区目的片段产物后纯化直接测序,筛选并确证潜在的单核苷酸多态性(SNP)位点,对SNP位点进行遗传特征分析,并与人类基因组单体型图(Hap Map)数据库中的不同人群分布数据进行比较。结果 PCR扩增和成功测序60名HBRA汉族人群(120条染色体)MGMT基因-875 nt~+362 nt的目的片段,序列比对发现该人群中6个已知SNP位点-797 G>A、-245 T>G、-177 T>G、-19 C>T、+73 C>T和+336 G>A,其最小等位基因频率分别为11.7%、0.8%、2.5%、15.8%、15.8%和29.2%。其中+336 G>A的等位基因频率在该人群的分布与Hap Map数据库中Hap Map-JPT和Hap MapCEU人种/人群的分布差异有统计学意义(P<0.05)。结论筛选出广东省HBRA汉族人群中MGMT基因5’侧翼区和第一编码区共6个SNP位点并提供其等位基因分布特征数据,为后续DNA多态性功能分析提供基础。
Objective To investigate the distribution of genetic polymorphisms of O6-methylguanine-DNA-methyltransferase (MGMT) gene in Han population of high background area (HBRA) in Guangdong Province. Methods A total of 60 HBR Han nationality in Guangdong Province were selected by random sampling method to obtain the peripheral blood genomic DNA. The 5 ’flanking region of MGMT gene and the target gene of the first coding region were amplified by polymerase chain reaction The SNPs were sequenced, screened and confirmed for potential SNP loci. Genetic characteristics of SNPs were analyzed and compared with the distribution data of different population in the Hap Map database of human genome Compare. Results The sequence of -875 nt ~ + 362 nt of the MGMT gene from 60 HBRA Han population (120 chromosomes) was sequenced and sequenced. Six known SNPs -797 G> A were found in this population. The minimum allele frequencies of -245 T> G, -177 T> G, -19 C> T, +73 C> T and +336 G> A were 11.7%, 0.8%, 2.5%, 15.8% 15.8% and 29.2%. The allele frequency of +336 G> A in this population distribution was significantly different from that of Hap Map-JPT and Hap Map CEU race / population distribution in Hap Map database (P <0.05). Conclusion A total of 6 SNP loci in the 5 ’flanking region and the first coding region of MGMT gene were screened out from the HBRA Han population of Guangdong Province and their allelic distribution data were provided, which provided the basis for the subsequent functional analysis of DNA polymorphism.