混合血迹中不同个体成份逐一分离识别的研究

目的研究法庭科学混合血迹物证中不同个体成份逐一分离、识别的问题,建立适合混合血迹个体识别的分析技术。方法采用PCR-SSCP及测序技术,选择m tDNA D-loop区的HVI 16030~16481区域452 bp片段作为分析目标,对中国汉族两无关个体、三无关个体混合血迹进行分析。结果100份两个体混合血迹样品m tDNA 452bp的PCR产物经SSCP电泳分离,结果有95份样品完全分离开,分离成功率达95%;30份三个体混合血迹样品452 bp片段经SSCP电泳分离,结果有26份样品有1~3个个体完全分离开,分离成功率达84%。对其中3份两个体混合血样、2份三个体混合血样SSCP电泳分离后的谱带进行回收、测序分析,两个体混合血样每一份均可准确获得其中单一个体序列及以另一个体主要成份(峰值比达4∶1以上)的序列结果;三个体混合血迹中不同个体成份可以达到初步分离,1份可准确确定单一个体序列。对两个体不同比例混合样品SSCP分析,结果可以检测到较少成份的最低比例为20∶80。结论本研究建立的PCR-SSCP及测序分析混合血迹综合技术,是对混合血迹中不同个体成份逐一分离、识别的一种有效技术手段。

The separation and identification of different individual components from mixed bloodstains

Objective To study the separation and identification of different individual components from the mixed bloodstains and establish relevant technology for forensic science.Methods the mixed bloodstains were composed of two or three unrelated individual components.The HVI 16030~16481 region of mtDNA was selected as an indicator for analyzing the mixed bloodstains.The PCR-SSCP typing and mtDNA sequencing technology were employed.Results The PCR-SSCP results showed that 100 bloodstains mixed with two individual components were separated with a successful rate of 95%,while 30 bloodstains mixed with three individual components were separated with a successful rate of 84%.The mixed stains with two individual components with different ratio can be distinguished with a minimum ratio of 20∶80.SSCP bands from the mixed stains with both two individuals and three individuals were retrieved and sequenced.For the mixed stains with two individuals,a single sequence from an individual and a mixed sequence with a sequencing peak ratio of 4∶1 were obtained.For the mixed stains with three individuals,only one individual can be observed as a single sequence.Conclusion The comprehensive technology of both PCR-SSCP and DNA sequencing can be effectively employed to separate and identify different components of the mixed bloodstains.It is valuable in forensic practice.