抗污染扩增试剂在法医物证检验中的应用

Application of Anti-contamination Amplifi cation Reagents inForensic Biological Evidence Examination

客观、准确的法医遗传检验结果是作出准确鉴定意见的基础。随着检验设备、扩增检测试剂检验灵敏度日益增加,防控实验室污染、样品污染的压力与日俱增,其中PCR扩增产物对检测结果的污染最难防控。本文测试一款抗污染扩增试剂盒NH-18A,该试剂盒包含16个常染色体STR基因座,1个性别识别基因座(Amel)和一个Y染色体插入缺失基因座(Indel),NH-18A通过STR复合扩增可得到含有尿嘧啶碱基的DNA片段,该类型的DNA片段在50℃时可被尿嘧啶DNA糖基化酶(UDG)高效水解,每次新一轮PCR扩增前增加一步50℃保温孵育可以彻底消除既往扩增产物对结果的污染威胁。经实验验证,NH-18A具有优异的抗扩增产物污染能力,且替换碱基扩增不改变DNA分型结果,检测灵敏度和DNA产物片段稳定性不降低,后续电泳分析不受影响。利用此试剂盒可以有效消除扩增产物对鉴定结果的污染。

Objective and accurate forensic genetic analysis results are the basis for making accurate identification opinions.With the increasing sensitivity of testing equipment and amplification kits,the pressure to prevent laboratory pollution is increasing.Among them,the contamination of PCR amplifi cation products is the most diffi cult type of pollution to prevent.This research introduces an anti-pollution amplifi cation kit,which contains 16 short tandem repeats(STR)locus,one sex identifi cation locus(Amel)and one Y chromosome insertion deletion locus(Indel).Anti-pollution amplifi cation kit can obtain DNA fragment containing uracil base through STR multiplex amplifi cation,and this type of DNA fragment can be effi ciently hydrolyzed by uracil DNA glycosylase(UDG enzyme)at 50℃.An additional 50℃incubation before each new round of PCR amplifi cation can completely eliminate the pollution threat of previous amplifi cation products to the results.After testing,the anti-pollution amplifi cation kit has excellent anti-pollution ability,and uracil base does not change the DNA typing results.Its detection sensitivity does not decrease;the stability of DNA product fragments does not decrease;and subsequent electrophoresis analysis is not affected.This reagent kit can effectively eliminate contamination of amplifi cation products.