[Establishment of miniSTR fluorescent detection system and its forensic application]

To establish miniSTR fluorescent detection system with all detected fragments below 150 bp and to enhance the efficiency of detecting the degraded DNA samples.

All candidate primers were designed by Primer Premier 5 and screened by FastPCR 6.0. The miniSTR multiplex system was established by these selected loci labeling by four fluorescent dye. The parameters of PCR and primer concentrations were subsequently optimized. The electrophoresis was fulfilled under POP4 on 3100-Avant and the typing data was validated by standard DNA 9947A and 007. Fresh blood samples and difficult degraded DNA samples were tested to evaluate the usefulness of the system.

All amplicons in the established miniSTR fluorescent detection system (D12ATA63, D2S1776, D1GATA113, D4S2408, D17S974, D20S482, D3S3053, Amelogenin, D6S474, D9S1122) were less than 150bp. The profile showed a balanced peak height without extra stutter by optimal protocol. Allele frequencies showed no deviations from Hardy-Weinberg equilibrium. The system showed accumulated probability of discrimination 0.999 999 983 and accumulated triplet excluding probability of paternity 0.996 8. It could detect corrupt muscle tissue, low copy number DNA samples and human tissues fixed by 40% formaldehyde solution for 12 days.

The miniSTR fluorescent detection system could be solely used for personal identification of degraded DNA samples or complementally used for paternity tests. And the system could enhance the ability of detecting the trace and degraded DNA.