EVALUATION OF Y-CHROMOSOMAL STRS - A MULTICENTER STUDY

A multicenter study has been carried out to characterize 13 polymorphi c short tandem repeat (STR) systems located on the male specific part of the human Y chromosome (DYS19, DYS288, DYS385, DYS388, DYS389I/II, DYS390, DYS391, DYS392, DYS393, YCAI, YCAII, YCAIII, DXYS156Y). Amplif ication parameters and electrophoresis protocols including multiplex a pproaches were compiled. The typing of non-recombining Y loci with uni parental inheritance requires special attention to population substruc turing due to prevalent male lineages. To assess the extent of these s ub-heterogeneities up to 3825 unrelated males were typed in up to 48 p opulation samples for the respective loci. A consistent repeat based n omenclature for most of the loci has been introduced. Moreover we have estimated the average mutation rate for DYS19 in 626 confirmed father son pairs as 3.2 x 10(-3) (95% confidence interval limits of 0.00041- 0.00677), a value which can also be expected for other Y-STR loci with similar repeat structure. Recommendations are given for the forensic application of a basic set of 7 STRs (DYS19, DYS389I, DYS389II, DYS390 , DYS391, DYS392, DYS393) for standard Y-haplotyping in forensic and p aternity casework. We recommend further the inclusion of the highly po lymorphic bilocal Y-STRs DYS385, YCAII, YCAIII for a nearly complete i ndividualisation of almost any given unrelated male individual. Togeth er, these results suggest that Y-STR loci are useful markers to identi fy males and male lineages in forensic practice.