Developmental validation of the AGCU EX-38 typing system: a comprehensive forensic tool for enhanced genetic identification

The necessity for developing the AGCU EX-38 typing system arises from the ever-increasing demand for more accurate and comprehensive forensic tools. Traditional kits with fewer STRs often fall short in complex cases requiring higher resolution. The AGCU EX-38 typing system incorporates 35 autosomal STRs, including extended CODIS loci as well as additional non-CODIS loci (D6S1043, D19S3045, D3S3045, D7S3048, D11S2368, D4S2366, D8S1132, D15S659, Penta D, Penta E, D6S447, D3S1744, D14S608, D18S535). This combination of CODIS and non-CODIS markers provides a significant advantage, particularly in complex kinship analyses such as half-sibship cases. This six-dye kit encompasses 38 loci, with a maximum amplicon size of 550 base pairs (bp), and features nine STRs within 200 bp and 14 STRs within 300 bp, offering unparalleled coverage and sensitivity. The AGCU EX-38 typing system is the only available kit on the market containing 35 autosomal STRs with six-dye chemistry, making it a unique and invaluable resource for forensic laboratories. This configuration allows for higher resolution and superior performance in cases with degraded or mixed DNA samples. In this study, we report the results of the developmental validation study, which followed the SWGDAM (Scientific Working Group on DNA Analysis Methods) guidelines. The data includes PCR-based studies, sensitivity, species specificity, stability, precision, reproducibility and repeatability, concordance, stutter, DNA mixtures, and performance on mock casework samples. The results validate the multiplex design and demonstrate the kit's robustness, reliability, and suitability for genetic identification and population studies.