Design and validation of a highly discriminatory 10-locus Y-chromosome STR multiplex system

The Y-chromosome STRs (short tandem repeat) markers are routinely utilized in the resolution of forensic casework related to sexual assault. For this, the forensic community has adopted a set of eleven (core) Y-STR that is incorporated in all commercial diagnostic systems. Our previous studies of Y-STR polymorphisms in the South African population identified low levels of diversity and discrimination capacity for many commercial marker sets, determining a limited applicability of these systems to the local population groups. To overcome this shortcoming, we designed a Y-STR 10-plex system that shows higher discriminatory capacity (DC) than available commercial systems. The markers were selected from a population group of 283 individuals with African, European and Asian ancestry genotyped at 45 Y-STRs, applying an optimization based selection procedure to achieve the highest possible DC with the minimal number of markers. The 10-plex was satisfactorily subjected to developmental validation tests following the SWGDAM guidelines and shows potential for its application to genealogical and evolutionary studies.