Objective: To investigate the feasibility of applying multiple displacement amplification (MDA) to DNA typing in forensic pathological section.
Methods: Ninety-eight pieces of pathological sections were prepared in terms of 3 factors as the period of preservation, tissue types and death ages, and randomized into groups by Latin square by double 7-order design. Silicon bead method was used to extract the DNA template. Compared with the PCR amplification performed directly by AmpFlSTR Identifiler kit in the control group, MDA was performed before amplification in the experimental group. Based on the samples from fresh autopsies as the standard genotypes, the number of detection and the detection rate were analyzed and compared between the experimental group and the control group.
Results: Between the control group and the experimental group, there was significantly statistical difference regarding the rate of DNA typing in each period of the tissue sections preserved (P<0.01). The detection rate of the 16 loci in the experimental group was more than 95% when the period of the tissue sections were preserved within 360d. There was significant difference in different tissue types (P<0.01). But there was no significant difference in different death ages (P>0.01).
Conclusion: MDA is efficacious in DNA typing of forensic pathological sections, for it can improve the DNA template quantification through abating the inhibiting factor's concentration of PCR and reducing the rate of allele drop out (ADO). However, the period of the sections preserved and tissue types would affect the results of genotyping by MDA.