Objectives: To explore the feasibility of genetic marker detection of semen-specific coding region single nucleotide polymorphism (cSNP) based on SNaPshot technology in semen stains and mixed body fluid identification.
Methods: Genomic DNA (gDNA) and total RNA were extracted from 16 semen stains and 11 mixtures composed of semen and venous blood, and the total RNA was reverse transcribed into complementary DNA (cDNA). The cSNP genetic markers were screened on the validated semen-specific mRNA coding genes. The cSNP multiplex detection system based on SNaPshot technology was established, and samples were genotyped by capillary electrophoresis (CE).
Results: A multiplex detection system containing 5 semen-specific cSNPs was successfully established. In 16 semen samples, except the cSNP located in the TGM4 gene showed allele loss in cDNA detection results, the gDNA and cDNA typing results of other cSNPs were highly consistent. When detecting semen-venous blood mixtures, the results of cSNP typing detected were consistent with the genotype of semen donor and were not interfered by the genotype of venous blood donor.
Conclusions: The method of semen-specific cSNPs detection by SNaPshot technology method can be applied to the genotyping of semen (stains) and provide information for determining the origin of semen in mixed body fluids (stains).
目的: 探讨基于SNaPshot技术的精液特异性编码区单核苷酸多态性（coding region single nucleotide polymorphism，cSNP）遗传标记检测在精液（斑）溯源及混合体液（斑）鉴定中的可行性。方法: 制备16例精液斑和11例精液-静脉血混合斑样本，提取其基因组DNA（genomic DNA，gDNA）和总RNA，并将总RNA逆转录为互补DNA（complementary DNA，cDNA）。在已验证的精液特异性mRNA编码基因上筛选cSNP遗传标记。基于SNaPshot技术构建cSNP复合检测体系并通过CE对样本进行基因分型。结果: 成功构建了包含5个精液特异性cSNP的复合检测体系。在16例精液样本中，除了位于TGM4基因上的cSNP在cDNA的检测结果中出现等位基因丢失外，其余cSNP的gDNA和cDNA分型结果高度一致。检测精液-静脉血混合斑时，检出的cSNP分型结果均与精液提供者的基因型一致，未受到静脉血提供者基因型的干扰。结论: 应用SNaPshot技术检测精液特异性cSNP的方法可以应用于法医学精液（斑）的基因分型，并为混合体液（斑）中精液来源个体的判定提供信息。.
Keywords: SNaPshot method; body fluids identification; coding region single nucleotide polymorphism; forensic genetics; mixture analysis; semen.