人体接触检材前处理方式对磁珠法提取DNA效果的影响

The effects to the touch DNA extraction by the magnetic beads method with three preprocess protocols

目的比较3种常见的接触检材前处理方式对磁珠法提取DNA效果的影响。方法收集烟蒂、牙刷、纱线手套各10份;分别采用95℃、70℃直接裂解和TNE、SDS、PK预消化方式进行前处理,再用磁珠法提取纯化DNA,并进行DNA定量,统计提取的接触DNA量和IPC CT值;同时用Sinofiler复合扩增系统进行STR分型检测。结果 3种方法前处理后用磁珠提取的DNA纯度均较高I,PC CT值在26.63～27.19之间。用预消化法获得的DNA量高于裂解法,而95℃裂解与70℃裂解方法提取的DNA量无显著性差异。STR扩增检测结果亦表明,采用预消化法处理的样品STR分型成功率高于裂解法9,5℃与70℃裂解方法处理的样品STR分型成功率无显著性差异。结论人体接触检材采用预消化磁珠法提取DNA,有助于提高STR检验成功率。

Objective To compare the touch DNA extraction effects by the magnetic beads method with three preprocess protocols.Methods DNA were extracted from 10 cigarette butts,10 toothbrushes and 10 gloves by DNA IQ magnetic beads method respectively after 95℃,70℃ direct lysis and digested with TNE,SDS and proteinase K.The comparison were performed with DNA amounts,IPC CT and the typing results of Sinofiler system.Results The value of IPC CT for all DNA extracted by the magnetic beads methods after three preprocess protocols was between 26.63 and 27.19,which meaned high purity.Digesting samples with TNE,SDS and proteinase K before the magnetic beads purification yielded more DNA than using direct lysis protocols,and the success rate of STR typing by the digesting protocol was accordingly higher than that of the direct lysis protocols.Whether 95℃ or 70℃ direct lysis treatment,however,no significant difference was observed in both DNA yield and the success rate of STR typing.Conclusion The success rate of STR typing for touch DNA samples can be increased by the digesting protocol before the magnetic beads purification.