Validation study of 6 dye-based SF25™ PCR amplification kit

Abstract

Ever since the inception of STR-based forensic DNA analysis for human identification and DNA profiling, the approach developed continuously. Most of these developments are pertaining to achieve the set of best polymorphic loci for analysis, high inhibitor tolerance capability, and increase in sensitivity, reduction in turnaround time, and cost-effectiveness. On the similar line, the SF25™ PCR amplification kit, a 6 fluorescent dye-chemistry based autosomal STR kit was developed, which analyses 25 STR loci viz., FAM fluorescent dye-labelled D3S1358, D13S317, D7S820, D16S539, D1S1656, and Penta E; HEX fluorescent dye-labelled TPOX, TH01, D2S1338, CSF1PO, and Penta D; SUM fluorescent dye-labelled D19S433, vWA, D21S11, D18S51, and D6S1043; LYN fluorescent dye-labelled Amelogenin, D8S1179, D5S818, D12S391, and FGA; PUR fluorescent dye-labelled D22S1045, Y-indel; D2S441 and D10S1248. The developmental validation of the SF25™ PCR Amplification reagents were carried out in this study to analyze its specificity, sensitivity, and concordance. This multiplex kit showed higher sensitivity with 125 pg of DNA template generating a complete profile (with 100% allele call). Out of 316 samples, 32samples showed aberrant triallelic pattern/aberrant heterozygous pattern at D16S539 locus. The possible discrepant homozygous condition at locus D1S1656 might be due to the invasion of alleles at D1S1656 locus present adjacent to D16S539 locus. Such invasion resulted due to the shortening of the allelic bin size at the D1S1656 locus. The allelic ladder of the SF25™ PCR amplification kit reveals the allelic range of D1S1656 from 11 to 19.3 which can be interpreted according to the casework as deemed by the end-users for their samples.