同源序列对CYP2A13基因SNP研究的影响

Interference of Homologous Sequences on the SNP Study of CYP2A13 Gene

背景与目的已有研究表明:细胞色素P450酶2A13(cytochrome P4502A13,CYP2A13)在单核苷酸多态性(single nucleotide polymorphisms,SNP)与疾病关联中起重要作用。细胞色素P450酶是一组同工酶,基因序列间有高度的同源性,可能对SNP分析产生影响。本研究初步探讨同源序列对CYP2A13基因SNP研究的影响。方法应用Taqman探针检测573例人群rs8192789位点的分布,采用BLAST方法分析引物结合序列。对60例样本的CYP2A13序列进行测序,进一步进行了TA克隆测序,应用BLAST方法分析了克隆测序结果。结果rs8192789位点在573例人群中只有3例为TT纯合型,其余均为CT杂合型,BLAST分析为同源序列导致。60例人群CYP2A13部分序列测序结果完全一致,有大量套峰,101氨基酸位点处没有dbSNP数据库中报道的SNP位点。克隆测序为247bp、235bp两个片段。结论CYP2A13的同源序列对SNP研究造成了干扰,部分SNP位点可能是不存在的。

Background and objective It has been proven that cytochrome P450 enzyme 2A13 （CYP2A13） played an important role in the association between single nucleotide polymorphisms （SNP） and human diseases.Cytochrome P450 enzymes are a group of isoenzymes,whose sequence homology may interfere with the study for SNP.The aim of this study is to explore the interference on the SNP study of CYP2A13 caused by homologous sequences.Methods Taqman probe was applied to detect distribution of rs8192789 sites in 573 subjects,and BLAST method was used to analyze the amplified sequences.Partial sequences of CYP2A13 were emplified by PCR from 60 cases.The emplified sequences were TA cloned and sequenced.Results For rs8192789 loci in 573 cases,only 3 cases were TT,while the rest were CT heterozygotes,which was caused by homologous sequences.There are a large number of overlapping peaks in identical sequences of 60 cases,and the SNP of 101 amino acid site reported in the SNP database is not found.The cloned sequences are 247 bp,235 bp fragments.Conclusion The homologous sequences may interfere the study for SNP of CYP2A13,and some SNP may not exist.