Study on STR markers of DNA for improving the power of identification on cases in Taiwan

Samples collected from 775 unrelated Chinese population in Taiwan were identified to obtain the allele frequencies for 20 DNA short tandem repeat (STR) loci (D3S1358, D1S1656, D6S1043, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433, FGA) included in the Promega PowerPlex® 21 system amplification kit. The values of observed heterozygosity (Ho) ranged from 0.5290 for TPOX to 0.9058 for Penta E, expected heterozygosity (He) ranged from 0.5862 for TPOX to 0.9122 for Penta E, polymorphism information content (PIC) ranged from 0.5267 for TPOX to 0.9058 for Penta E, power of discrimination (PD) ranged from 0.5460 for TPOX to 0.9833 for Penta E, the duos probability of paternity exclusion (PEduos) ranged from 0.1826 for TPOX to 0.7001 for Penta E and the trios probability of paternity exclusion (PEtjios) ranged from 0.3327 for TPOX to 0.8236 for Penta E were calculated. The five new markers (D1S1656, D6S1043, Penta E, Penta D and D12S391) of the Promega PowerPlex® 21 system were different from the AmpFLSTR® IdentifilerTM kit, which were identified to decrease the random match probability and got the result for increasing the discrimination over 106 times than Identifiler system that were very useful for confirming the source of trace evidence identification.