纸张上潜在手印三种前处理方法对DNA检验的影响

目的通过比较常见纸张上潜在手印盲提法与显现后精准提取法的接触DNA检出率,探讨常见纸张上接触DNA前处理的优选方案。方法比较五种常见纸张上使用盲提法和显现潜在手印(茚二酮显现法、茚三酮熏显法)后精准提取法采集的接触DNA样本检出率。结果粗糙日历纸盲提的接触DNA检出率为17.8%,通过茚二酮法和茚三酮法显现的潜在手印所提取的DNA检出率分别为75.6%、77.8%;光滑日历纸三种方法所提取的接触DNA检出率为4.4%、11.1%、11.1%;A4复印纸三种方法接触DNA检出率为20%、37.8%、66.7%;牛皮纸三种方法接触DNA检出率为20%、68.9%、64.4%;快递纸袋的三种方法接触DNA检出率为2.2%、6.7%、46.7%。结论不同纸张上潜在手印经显现后接触DNA检出率不同,通过茚二酮或茚三酮显示潜在手印后精准提取DNA的前处理方法相较于盲提法的接触DNA检出率高。实战中可应用此类方法同时获得手印与DNA分型,以有效提高证据力。

Comparison among influences of three pretreating methods on testing DNA from paper-harboring latent fingerprint

Objective Through comparison of detection rates of touch DNA on common paper between blind extraction of latent fingerprint and precise location after development, the optimal solution was to determine for pretreatment of common paper to have the harbored DNA tested. Methods Touch DNA samples were collected from five types of paper with both the blind extraction and precise location following fingerprint development (indanedione spraying or ninhydrin fuming), having their detection rates compared. Results For the rough calendar paper, the blind extraction method contributed the detection rate of touch DNA as 17.8%, contrasting to the respective 75.6% and 77.8% with either indanedione or ninhydrin to develop latent fingerprint beforehand. The smooth calendar paper presented the detection rates of touch DNA via the above three treatments as 4.4%, 11.1% and 11.1%, with those for A4 paper 20%, 37.8% and 66.7%, the ones from kraft 20%, 68.9% and 64.4% plus those about express delivery paper bag being 2.2%, 6.7% and 46.7%, individually. Conclusions The touch DNA is of distinct rate of detection on different common paper after development of their harboring latent fingerprints. The pretreating methods (indanedione spraying or ninhydrin fuming), enabling site-precise extraction of DNA at the position of fingerprint, can derive a higher detection rate of touch DNA than the blind extraction method. Practically, the way of DNA extraction at the site of fingerprint determination can obtain both the fingerprint and DNA genotyping simultaneously, thereby capable of improving the power of evidence. © 2021, Editorial Office of Forensic Science and Technology. All rights reserved.