Increased forensic efficiency of a STR-based Y-specific haplotype by addition of the highly polymorphic DYS385 locus.

The polymorphic short tandem repeat (STR) locus DYS385 mapping to the male-specific region of human Y chromosome, was used to reinvestigate 125 unrelated Italian males, from our data archive, who had been previously typed for 7 different Y-specific STRs (DYS19, DYS389 I and II, DYS390, DYS391, DYS392, DYS393), defining a haplotype now widely adopted in the forensic context. The aim of this study was to improve the information value of the original haplotype in view of its application to issues of personal identification and parental analysis. DYS385 proved to be highly polymorphic (94.5% gene diversity) and the overall individualization capacity of the 8-loci haplotype was raised to 93.6%, with 117 unique assets out of 125 tested samples.