物证袋保存生物检材产生DNA转移问题研究  

An Investigation of DNA Transfer onto Forensic Evidence Package

作　　者：董会[1,2,3] 王晶[1] 秦翠娇[1] 张涛[4] 贾竟[5] 叶健[1] 李彩霞[1] 刘超[2] 

机构地区：[1]公安部物证鉴定中心法医遗传学公安部重点实验室,北京100038 [2]广州市刑事科学技术研究所,广州510030 [3]南方医科大学基础医学院法医学系,广州510515 [4]新疆生产建设兵团公安局,乌鲁木齐830000 [5]郑州大学基础医学院,郑州450000

出　　处：《刑事技术》2016年第3期173-177,共5页Forensic Science and Technology

基　　金：国家自然科学基金项目(No.81202384);公安部技术研究计划项目(2014JSYJA011)

摘　　要：目的生物物证在运送至实验室检验时会保存在专用的物证袋中,物证袋转移的DNA越少越有利于检材的检验,本文研究两种物证袋在保存不同种类物证时是否发生DNA二次转移以及其转移率的差别。方法制备样本,模拟密封的塑料物证袋和纸质物证袋提取物证的过程,分别使用常规程序对物证袋和物证进行DNA提取、定量和扩增,并对各项结果进行分析和讨论。实验中使用了3种微量接触类样本和4种非微量接触类样本,样本制备完成后由工作人员通过行走等模拟样本的运输过程,样本直接剪碎进行DNA提取,而物证袋使用两步擦拭法进行前处理后再进行DNA提取。最终使用转移率来比较DNA转移情况。结果实验观察到100%的样本发生DNA转移,其DNA转移率平均为22.06%。纸质物证袋和塑料物证袋的转移率有差别(P=0.023),纸质物证袋和塑料物证袋的转移率分别为26.27%和17.85%,结论使用物证袋保存物证的过程中,会发生DNA转移造成潜在的DNA丢失,其转移率在不同类型的物证袋和不同类型的样本之间存在差别,并最终将会对分型结果产生影响。总体上微量接触类样本的转移率高于非微量接触类样本,纸质物证袋的转移率高于塑料物证袋。Objective Biological evidential material, enclosed in forensic evidence package, may be transferred onto its package, making the DNA typing less detectable. Therefore, the lower transfer level is better, especially for the trace touch DNA samples. This study aimed to investigate whether the DNA is transferred onto forensic evidence package and the transfer rate between different types of evidential materials and packages. Methods With two kinds of forensic evidence package, the seal-lock plastic bag and yellow paper envelope, three kinds of trace touch DNA, four blood and saliva samples were prepared to simulate the packaging and transporting process. An individual, carrying a suitcase which contained all of the test samples, walked on a treadmill（running at 4 km/h） for 30 min, then went up- and down-stairs for five stories. DNA, extracted from the test samples and the evidence packages, was quantified, amplified and analyzed following the manufacturer＇s standard procedures. The transfer rates were compared with two different packaging ways. Results The experiment showed that all of the test samples were transferred onto package at various levels and the average transfer rate was 22.06 %. The two types of packages were observed of significant difference（P=0.023） for their transfer rates, with those of the seal-lock plastic bag being estimated as 17.85 % and the yellow paper envelope as 26.27 %. The transfer rates of the trace touch samples were higher than those of the blood and saliva samples no matter whether they were kept in the yellow envelope or the seal-lock plastic bag. The loss of recoverable DNA from the samples to the evidence packages ranged from 1.84 % to 67.66 %. Conclusions DNA transfer occurs on the forensic evidence package to crop it, affecting DNA typing. Different types of samples have different transfer rates and so have the evidence packages.

关 键 词：法医物证学 二次转移 DNA分型 

分 类 号：D919.2[医药卫生—法医学]