Analysis of 30 Y-chromosomal STR markers in the Norwegian population

Abstract

Autosomal STR-analysis is the standard method of DNA-typing in casework. However, there are forensic sample types that may contain a large fraction of female DNA and a minimal fraction of male DNA. The male fraction may not be successfully amplified using autosomal STR-analysis because it “drowns” in the female fraction. However, the analysis of male-specific YSTR markers may circumvent this obstacle. The purpose of this study was to analyze YSTR markers in the Norwegian population. Two analysis kits based on different technologies, capillary electrophoresis and next generation sequencing, were used. Both fragment length and sequence information was obtained for YSTR alleles. The fragment length-based information is collected to be included in a reference database of YSTR haplotypes that can be used to calculate the statistical weight of the evidence upon a DNA-profile match. Several loci overlap between the two kits, and the concordance based on fragment length was high. Forensic parameters were calculated for both kits in order to evaluate the analytical power. Sequencing leads to an increase in allele variants, and many of the allele variants found are apparently novel.