The Improvements Of Traces DNA Testing Technology And Application In The Forensic Reconnaissance Detection

Objective:To establish the method of extracting fingerprint's DNA from the carrier of the permeability and non-permeability, to maximize the criminal investigation role of the fingerprint especially the incomplete forensic fingerprint, and providing a scientific basis for the criminal investigation.Methods:Using self-developed sweat latent fingerprints DNA extracted reagentto extract fingerprint's DNA, then amplified the fingerprint's DNA by our improved MDA amplification method, and genotyped by AmpFlSTR(?) IdentifilerTM PCR Amplification Kit,PowerPlex(?) 16 System and GoldeneyeTM 20A Kit.Results:For the template of 5pg 16 STR loci genotyping,12 loci were detected, while the Sigma WGA method can only detect 4 loci. After extracting the fingerprint DNA on non-permeable carrier-glass slide with latent fingerprint DNA extracting buffer, the improved MDA method was used to amplify, then genotyped 16 STR loci by AmpFlSTR(?) IdentifilerTM PCR Amplification Kit,9 STR loci were detected..Comparing with different carriers, different extraction method, different amplification method in the experiment, the fingerprint DNA on slide was easier to be extracted than on paper, and sweat latent fingerprints DNA extracted reagentwas more efficient than 5% chelex-100 extraction for genotyping, and modified MDA amplification method wasmore efficient than WGA for amplification.Conclusion:Improved MDA method can significantly increase the efficiency of trace template DNA typing,The allele bias still exist during DNA typing of fingerprint, the experimental methods could be improved by instead STR markers of SNP markers.