Recently, the Yfiler® Plus PCR Amplification Kit (Yfiler® Plus, Thermo Fisher Scientific,
Waltham, MA, USA) was introduced. Yfiler® Plus amplifies 27 Y-chromosomal short tandem
repeat loci (Y-STRs) and adds ten new Y-STRs to those analysed with the commonly used
AmpFlSTR® Yfiler® PCR Amplification Kit (Yfiler®, Thermo Fisher Scientific, Waltham,
MA, USA). Seven of the new Y-STRs are rapidly mutating Y-STRs (RM Y-STRs). In this
study, 551 male individuals from Denmark, Greenland and Somalia were typed with Yfiler®
Plus. The results were compared to those obtained with Yfiler® in the same individuals.
Forensic and population genetic parameters were estimated for Yfiler® Plus. Yfiler®
Plus had a higher power of discrimination than Yfiler® in all three populations. Compared
to Yfiler®, Yfiler® Plus offers increased power of discrimination, which is obviously
an advantage in crime case investigations. However, the inclusion of seven RM Y-STRs
in Yfiler® Plus makes it less attractive for relationship testing because of the relatively
high combined mutation rate, approximately 15%.