SNPlexing the human Y-chromosome: a single-assay system for major haplogroup screening.

SNPs are one of the main sources of DNA variation among humans. Their unique properties make them useful polymorphic markers for a wide range of fields, such as medicine, forensics, and population genetics. Although several high-throughput techniques have been (and are being) developed for the vast typing of SNPs in the medical context, population genetic studies involve the typing of few and select SNPs for targeted research. This results in SNPs having to be typed in multiple reactions, consuming large amounts of time and of DNA. In order to improve the current situation in the area of human Y-chromosome diversity studies, we decided to employ a system based on a multiplex oligo ligation assay/PCR (OLA/PCR) followed by CE to create a Y multiplex capable of distinguishing, in a single reaction, all the major haplogroups and as many subhaplogroups on the Y-chromosome phylogeny as possible. Our efforts resulted in the creation of a robust and accurate 35plex (35 SNPs in a single reaction) that when tested on 165 human DNA samples from different geographic areas, proved capable of assigning samples to their corresponding haplogroup.