A Simple Method of VNTR D1S80 Locus Allelic Ladder Construction for Capillary Electrophoresis-based Genotyping.

VNTR D1S80 locus genotyping has been largely replaced in forensics by STR. As the statute of limitations on murder cases was abolished in the Republic of Korea in July 2015, the demand for re-analysis of DNA from unresolved murder cases has increased. The National Forensic Service includes several recorded D1S80 genotypes as crucial clues. Here, we re-established the D1S80 analysis system using capillary electrophoresis and confirmed the reproducibility of the system by comparison with the genotypes of eight DNA samples that had been analyzed using PAGE in 2006. In addition, we created an allelic ladder via new methodology using flanking region sequences. A single DNA sample (K562) and seven primers were used for the new ladder, which contains 12 alleles. Although artificial owing to the use of the flanking region rather than repeat unit reduction, the method is rapid and simple, and could be applicable in any laboratory.

Evaluation of forensic genetic parameters of 12 STR loci in the Korean population using the InvestigatorⓇ HDplex kit.

We genotyped and calculated the forensic parameters of 10 non-CODIS loci and 2 CODIS loci of 990 Korean individuals using the InvestigatorⓇ HDplex kit. No significant deviations from Hardy-Weinberg equilibrium (after Bonferroni correction for multiple testing) or genetic linkage disequilibrium were observed. The calculated matching probability and power of discrimination ranged from 0.0080 to 0.2014, and 0.7986 to 0.9920, respectively. We conclude that the markers of the kit are highly informative corroborative tools for forensic DNA analysis.

Forensic genetic study of 29 Y-STRs in Korean population.

In this study, we compared two recently released commercial Y-chromosomal short tandem repeat (Y-STR) kits: the PowerPlex Y23 System (PPY23) and Yfiler® Plus PCR amplification kit (YPlus). We performed validation studies, including sensitivity, tolerance to PCR inhibitors, and mixture analysis, and a population genetics study using 306 unrelated South Korean males. PPY23 and YPlus showed similar sensitivity, but PPY23 showed higher tolerance to humic acid than YPlus. Furthermore, the detection rate of unique minor alleles called from male/male mixtures was higher for PPY23 than for YPlus. Comparing the newly added loci, the mean values of gene diversity for PPY23 and YPlus were 0.6715 and 0.8158, respectively. The discrimination capacity in the 306 unrelated South Korean males for PPY23 was 0.9837, and that for YPlus was 0.9935. These results will inform the selection of suitable Y-STR kits based on the purpose of forensic DNA analysis.