印记基因KCNQ1的遗传多态性及在亲权鉴定中的应用

Genetic polymorphim of the STR locus in intron 1a of imprinted gene KCNQ1 and its application in paternity testing

目的为了调查印记基因KCNQ1的STR位点在中国汉族人群中的遗传多态性,利用亲源印记等位基因(parentally imprinting allele,PIA)分型法确定孩子的等位基因亲代来源,为亲权鉴定提供新的侯选STR位点。方法应用Chelex法提取153例佳木斯地区汉族健康无血缘关系个体DNA,用QIAamp Blood Kit(Qiagen)法提取3个家庭10个个体DNA,PCR扩增,凝胶电泳分型,ABIPRISMTM3730XL DNA测序仪测序;甲基化敏感性限制性内切酶消化孩子基因组DNA,PCR扩增,确定孩子等位基因的亲代来源。结果发现在中国佳木斯地区汉族人群中KCNQ1基因的STR有7个等位基因,多态信息含量为0.662,且KCNQ1基因的STR位点呈父源印记。结论印记基因KCNQ1的STR位点有很好的多态性,可为亲权鉴定提供新的侯选遗传标记,其亲源特异性甲基化标记有望应用于单亲鉴定中。

Objective To investigate the genetic polymorphism of the STR locus at KCNQ1 gene in Han population, and to determine the inheritance of the paternal allele by PIA tying. Methods We collected 153 blood samples from the healthy and unrelated individuals in Jiamusi city. The DNA was extracted with Chelex method and amplified by PCR. The PCR products were analyzed using both the polyacrylamide gel electrophoresis and ABIPRISM^TM 3730XL DNA sequencer. Parentally imprinting allele （PIA） typing was applied to three families consisting of 10 individuals in which DNA was extracted with QIAamp Blood Kit （Qiagen）. Children＇s genomic DNA was digested by methylation-sensitive restriction endonucleases, followed by PCR amplification, and the products were analyzed by polyacrylamide gel electrophoresis. Results 7 alleles were observed for the STR locus in intron 1a of KCNQ1 gene in Chinese Han population in Jiamusi, and the polymorphism information content （PIC） was 0. 662. The KCNQ1 gene was a paternally imprinted gene. Conclusion This locus is highly polymorphic. The parental origins of alleles in an individual can be determined by PIA typing, and this technique can be used in forensic science as a valuable tool.