ABSTRACT
In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent.
Subject(s)
Chromosomes, Human, Y , Haplotypes , Microsatellite Repeats , Alleles , Forensic Genetics , HumansABSTRACT
The PowerPlex® Y23 System combines the seventeen Y-STR loci in current commercially available Y-STR kits (DYS19, DYS385a/b, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, and Y-GATA-H4) with six new highly discriminating Y-STR loci (DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643). These six new loci have higher gene diversities than most of the loci in other commercial Y-STR analysis kits, allowing for further distinction between unrelated male individuals. In addition, the inclusion of two rapidly mutating Y-STR loci may allow for the discrimination of related individuals. The PowerPlex® Y23 System is designed to amplify DNA from purified extracts as well as direct amplification from substrates used to collect database samples (e.g. swabs and storage cards). Validation of the PowerPlex® Y23 System includes all of the studies required by the FBI and SWGDAM. The results demonstrate that the PowerPlex® Y23 System is a robust and reliable amplification kit capable of overcoming high concentrations of commonly encountered inhibitors such as hematin, humic acid, and tannic acid. Full profiles are consistently detected with 62.5 pg of male DNA, even in the presence of excessive amounts of female DNA, establishing the PowerPlex(®) Y23 System as a sensitive method for Y-STR testing. Complete Y-STR profiles are detected from mixed samples with 62.5 pg of male DNA in a background of 400 ng of female DNA or 125 pg of male DNA mixed with 3000 ng of female DNA.
