Two Mini-STR Multiplex Systems For Degraded DNA Samples And The Test Of The Sensitivity

Objective：Recently the analysis of short tandem repeats（STRs）is a commonmethod of human DNA research，it always being used in the reconstruction ofkinship，identification and authentication. Here we set up two kind of mini-STRmultiplex PCR system to detect the STRs loci of degraded DNA samples.Methods: The system I contains the amplification of five CODIS STRs lociD13S317, D21S11, D5S818, FGA, Amelogenin and the system II contains theamplification of four non-CODIS STRs loci D1S1171, D2S1242, D3S1545, D4S2366.We designed five pairs of primers for the system I and the amplicons of this system isbelow200bp, each forward primer was labeled with fluorescence dyes6FAM,HEX,NED. For the system II we refer to the primers designed by H.Asamura（2）2007，primer was labeled with fluorescence6FAM,VIC,NED,PET.then we do aserious of analysis to optimize the parameters of the PCR system and Tm value.furthermore we make the allelic ladder from200blood samples from han people in norelationship.We analysis a serial dilutions of control DNA9947to evaluate the sensitivity，then we choose one blood sample which was digested by DNase I, in order tovalidate the sensitivity and efficiency, we choose DNA extracted from stale bonesample to test using these two kind of mini-STR multiplex PCR system.Result: Using the systems we were able to reproducibly obtain full STR profiles,the system I with a concentration of0.125ng-50ng DNA and the system II with aconcentration of0.63-50ng，the power of data reproduction of system I was68-83%and system II was69-85%，these two system can be used in the analysis of highlydegrade DNA sample and the species-specificity is good. Conclusion：Here we successfully repesent two high-efficiency amplificationsystems for highly degraded DNA samples. And the detection rate and sensitivity arereally high.