26-locus Y-STR typing in a Bhutanese population sample

26 Y-chromosome short tandem repeat (STR) loci were amplified in a sample of 856 unrelated males from Bhutan, using two multiplex polymerase chain reaction (PCR) assays. The first multiplex is the Y-STR 20plex described by Butler et al. (2002), and the second is a novel (but overlapping) 14plex that targets six additional Y-STRs (DYS425, DYS434, DYS435, DYS436, DYS461, DYS462) and also amplifies the amelogenin locus. The 26 loci give a discriminating power of 0.9957, though even at this resolution one haplotype occurs 24 times. We identify novel alleles at five loci, and microvariants at a further three, which were characterised by sequencing. Extended (11-locus) haplotypes for these samples have been submitted to the Y-STR Haplotype Reference Database.