汗潜指印STR分型的初步研究

目的:探讨遗留在签字笔上的汗潜指印DNA分型的可行性及其保存时间对分型的影响。方法:119支签字笔按照使用后保存时间分为7组,17名志愿者分别使用7支签字笔,每天20min,为期1个月,分别保存1d、3d、5d、7d、14d、21d和28d,运用Chelex-100法提取签字笔上遗留汗潜指印中的DNA,应用荧光标记PCR-STR技术进行DNA分型。同时采集上述17名志愿者口腔拭子进行DNA分型对照。分析签字笔作为检材进行DNA分型的可行性,及保存时间对DNA分型的影响。结果:以基因座检出个数为指标,签字笔上汗潜指印和口腔拭子随保存时间变化进行DNA分型的差异具有统计学意义(P<0.01)。使用后签字笔保存1d、3d、5d、7d、14d、21d和28d后进行DNA分型检出的基因座个数与对应的口腔拭子DNA分型检出的基因座个数相比差异均有统计学意义(P<0.01)。签字笔使用后保存1d进行DNA分型,可明确判读12个以上基因座的占11.8%。结论:签字笔上汗潜指印可作为一种法庭生物检材进行DNA分型,但其保存时间会影响DNA分型。

Preliminary study on STR typing of sweat latent fingerprint

Objective:To explore the feasibility of the short tandem repeat(STR) typing of the remainder of cells in sweat latent fingerprints on the fountain pen and the influence of conservation length on DNA typing. Methods: 119 fountain pens were randomly assigned to 17 volunteers with 7 to each individual. The volunteers were supposed to use their pens 20 min a day within a month, and these pens were kept for 1 d, 3 d, 5 d, 7 d, 14 d, 21 d and 28 d, respectively, after the behavior. In addition, the oral swabs of above 17 volunteers were collected as control group. Chelex-100 method was used to extract DNA remained in the sweat latent fingerprints of fountain pens and the oral swabs, and fluo-labelled PCR-STR technology was carried out to identify DNA typing. The number of gene loci detected was used as index for assessing the quality of DNA, thereby we explored the feasibility of employing used fountain pen as a biological material for identifying STR typing, and analyzed the influence of conservation time on STR typing. Results:With progress of conservation time, the differences of STR typing in sweat latent fingerprint and oral swabs had statistical significance(P<0.01), respectively. Compared with control group, the number of gene loci in exfoliated cells of fingers on pens after being preserved 1 d, 3 d, 5 d, 7 d, 14 d, 21 d or 28 d were decreased in total (P<0.01). The ratio, which the number of detectable gene loci in exfoliated cells of fingers after 1 d was more than 12, was 11.8%. Conclusion:The sweat latent fingerprints on fountain pen can be used as biological samples for STR typing in forensic science, but the conservation time would influence on the results of STR typing.