Short communication A substantially lower frequency of uninformative matches between 23 versus 17 Y-STR haplotypes in north Western Europe Maarten H.D. Larmuseau a,b,c, *, Nancy Vanderheyden a , Anneleen Van Geystelen d , Ronny Decorte a,b a UZ Leuven, Laboratory of Forensic Genetics and Molecular Archaeology, Leuven, Belgium b KU Leuven, Department of Imaging & Pathology, Biomedical Forensic Sciences, Leuven, Belgium c KU Leuven, Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, Leuven, Belgium d KU Leuven, Laboratory of Socioecology and Social Evolution, Department of Biology, Leuven, Belgium 1. Introduction The unique biology of the male-specific region (MSR) of the human Y-chromosome has led to the widespread use of Y- chromosome molecular markers in forensic studies, as well as in evolutionary, genealogical and anthropological research [1]. The analysis of the human MSR provides a powerful tool in forensic cases for male sex identification, male lineage identifica- tion and identification of the geographical origin of male lineages [2,3]. The focus of these forensic DNA typing applications has been on short tandem repeats of the Y-chromosome (Y-STRs) due to their higher heterozygosity and mutation rate in comparison with other Y-chromosomal markers such as single nucleotide poly- morphisms (Y-SNPs) [4]. Until today, forensic laboratories have been generating Y-chromosome haplotypes mainly based on two commonly used Y-STRs sets: the 12 Y-STRs included in the commercial kit PowerPlex Y 1 System (Promega) and the 17 Y-STRs found in the commercial kit AmpFlSTR Yfiler 1 PCR Amplification Kit (Life Technologies). Despite the robustness of the commercial multiplex Y-STR systems and the ability to discriminate between Forensic Science International: Genetics 11 (2014) 214–219 A R T I C L E I N F O Article history: Received 21 January 2014 Received in revised form 3 April 2014 Accepted 5 April 2014 Keywords: Y chromosome Y-STRs Discrimination capacity Familial DNA searching Genetic genealogy Surname A B S T R A C T The analysis of human short tandem repeats of the Y-chromosome (Y-STRs) provides a powerful tool in forensic cases for male sex identification, male lineage identification and identification of the geographical origin of male lineages. As the commonly used 12 and 17 Y-STR multiplexes do not discriminate between some unrelated males, additional Y-STRs were implemented in the PowerPlex 1 Y23 System to supplement the existing commercial Y-STR kits. Until today, the forensic value of a (near) 23 versus 17 Y-STR haplotype match between an unknown DNA donor and a certain biological sample in a database is not yet well studied. This will be of huge interest for cases where an autosomal DNA profile yields no match to a DNA database and the database is used for familial searching (male relative(s) of the offender) or for the estimation of the geographical origin of the offender. In order to value (near) 23 Y-STR haplotype matches in a local sample from Western Europe, we selected the region of Flanders (Belgium) due to the already present knowledge on its Y-chromosomal variants. Many Y-chromosomes of this region were previously genotyped with Y-SNPs at a high resolution of the most recently updated Y- chromosomal tree and the deep-rooted genealogy of each DNA donor was already established. By comparing (near) matches of 23 versus 17 Y-STR haplotypes between patrilineal-unrelated males, a substantial lower number of uninformative (near) 23 Y-STR haplotype matches has been observed compared to 17 Y-STR haplotypes. Furthermore, the use of SNP data was informative to discriminate >60% of unrelated males with an (near) identical 17 Y-STR match while SNP data was only necessary to discriminate about 10% of unrelated males with a 23 Y-STR haplotype that differed at only two Y-STRs. This shows the higher value of the Y23 haplotype within familial DNA searching and the estimation of the geographical origin of a DNA donor. Therefore, the use of the PowerPlex 1 Y23 System instead of the commonly used 12 and 17 Y-STRs by the forensic community is recommended as it will increase the efficiency of Y-STRs in forensic casework. ß 2014 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Katholieke Universiteit Leuven, Forensic Medicine, Kapucijnenvoer 33, B-3000 Leuven, Belgium. Tel.: +32 16 33 66 63; fax: +32 016324575. E-mail address: maarten.larmuseau@bio.kuleuven.be (M.H.D. Larmuseau). Contents lists available at ScienceDirect Forensic Science International: Genetics jou r nal h o mep ag e: w ww .elsevier .co m /loc ate/fs ig http://dx.doi.org/10.1016/j.fsigen.2014.04.002 1872-4973/ß 2014 Elsevier Ireland Ltd. All rights reserved.