Joint recommendations of the project group Statistical analysis of DNA and the German Stain Commission on the statistical analysis of YaEurochromosomal DNA typing results

The analysis of YaEurochromosomal short tandem repeats (Y-STRs) can be an important supplement to the established autosomal DNA analysis. For example, it is often possible to obtain information on the male component of a DNA mixture, even if there is an excess of female DNA. A Y-STR typing result can prove that male DNA is present at a trace and can be compared with reference Y-STR typing results of male suspects. The recommendations presented here by the project group Statistical analysis of DNA of the state criminal investigation offices in cooperation with the German Stain Commission of the German Society of Legal Medicine are intended to support experts in the evaluation of YaEuroSTR typing results. Approaches to estimate the frequency of Y-STR haplotypes are presented as well as approaches to assess the match probability between Y-STR results. From this, recommendations are derived with the aim of a standardized framework to evaluate Y-chromosomal DNA typing results in forensic casework