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

Emma J Parkin,Thirsa Kraayenbrink,George L Van Driem,Karma Tshering Of Gaselô,Peter De Knijff,Mark A Jobling

doi:10.1016/j.forsciint.2005.10.008

Abstract

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. [J.M. Butler, R. Schoske, P.M. Vallone, M.C. Kline, A.J. Redd, M.F. Hammer, A novel multiplex for simultaneous amplification of 20 Y chromosome STR markers, Forensic Sci. Int. 129 (2002) 10–24], 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 (YHRD).

Highlights

Y-chromosomal short tandem repeats (STRs) are becoming increasingly widely applied in forensic analysis because of their malespecificity and the informativeness of the haplotypes they define
Primers for five of the remaining six Y-STRs and for amelogenin are as described by Bosch et al, 2002 [8], and those for DYS425 are as described by Jobling et al, 1996 [9]
There seems little reason to type this marker in forensic contexts, though as a slow-mutating STR it still has potential in evolutionary studies, and for our purposes allows comparison with other datasets

Summary

Introduction

Y-chromosomal short tandem repeats (STRs) are becoming increasingly widely applied in forensic analysis because of their malespecificity and the informativeness of the haplotypes they define. Because of the strong geographical structure of Y-chromosomal haplotype variation, the usefulness of Y haplotypes in forensic casework depends on the availability of accurate and extensive population databases. We describe our initial findings with Y-STRs, treating the Bhutanese sample as a single population; relationships between subpopulations and linguistic sub-groups, together with data on other genetic markers, will be described in future publications. Our choice of Y-STRs was governed by three factors: comparability with a broad range of published data sets on other populations, forensic utility, and efficiency of typing. These requirements were met in two multiplexes, one of which has been previously described [5] and amplifies 20. Y-STRs, and the other which is novel, and targets 13 Y-STRs, seven of which are shared with the 20plex, plus amelogenin

DNA samples

Y-STR multiplexes

Results and discussion