Reduced PCR cycling time amplification using AmpFℓSTR ® Identifiler ® kit

Validation of reduced volume VeriFiler™ Express PCR Amplification Kit for buccal swab samples extracted using Prep-n-Go™ Buffer

The efficiency of reduced volume PCR amplification was studied using the VeriFiler™ Express PCR Amplification Kit. Full (25 μL) and reduced (5 μL) volumes were tested in parallel to identify any differences in template DNA sensitivity and other electropherogram parameters. Both volumes produced full DNA profiles down to 0.08 ng/μL DNA concentration at 26 PCR cycles; however, reduced volume produced higher peak heights due to increased signal intensities. Significant difference (p‐value ≤ 0.05) in heterozygote peak height ratios was observed between both volumes, where the reduced volume threshold was lowered to 0.6 to accommodate all data points. However, no significant difference (p‐value > 0.05) was identified in the stutter ratios between both volumes. The analytical threshold for reduced volume was also determined to be 150 RFU with the presence of template DNA in PCR amplification. When the optimized reduced volume parameters were tested on DNA extracted from buccal swab samples using Prep‐n‐Go™ Buffer, good quality DNA profiles were produced. Overall, the reduced volume not only showed better results compared to the full volume, but also enable more samples to be processed with a PCR amplification kit, thus reduced the cost.

Population genetics data for 22 autosomal STR loci in European, South Asian and African populations using SureID® 23comp Human DNA Identification Kit

Allele frequency data for 22 short tandem repeat loci; D18S1364, D1S1656, D13S325, D5S2800, D9S1122, D4S2366, D3S1744, D12S391, D11S2368, D21S2055, D20S482, D8S1132, D7S3048, D2S441, D19S253, D10S1248, D17S1301, D22-GATA198B05, D16S539, D6S474, D14S1434 and D15S659 from the SureID^® 23comp Human DNA Identification Kit have been determined for unrelated individuals in European, South Asian and African populations. Deviations from Hardy-Weinberg equilibrium were observed in loci D1S1656 and D19S253 in European; D18S1364, D6S474 and D14S1434 in South Asian; and D9S1122 and D8S1132 in African populations (p-value <0.05). However, after Bonferroni correction no significant deviations were observed (p-value <0.002). The most discriminating loci were D1S1656 and D12S391 for European (PD=0.977), D21S2055 for South Asian (PD=0.980), and D21S2055 and D7S3048 for African (PD=0.972) populations. The match probabilities were 1 in 6.7×10²⁵ for European, 1 in 1.4×10²⁶ for South Asian and 1 in 1.6×10²⁶ for African populations. These findings established the high discriminatory capacity and robustness of the tested STR loci for forensic identification and kinship testing.