Impact of Additional Y-STR Loci on Resolving Common Haplotypes and Closely Related Individuals

Two commercial Y-chromosome STR kits are widely available for amplifying 12 or 17 Y-STR loci. Using these commercial kits as a starting point, this study screened additional loci in order to determine their ability to resolve U.S. population samples. After testing, 20 of these loci were assessed in conjunction with the Yfiler loci regarding their ability to resolve the most common haplotype observed in 656 U.S. population samples. Typing of these samples revealed a common haplotype that was observed 26 times with only the minimal haplotype that was observed 26 times with only the minimal haplotype loci; therefore, approximately 4 percent of the samples were unresolved using these nine loci. Adding DYS438 and DYS439 loci breaks these samples into three groups. The additional locus DYS437 on the Powerplex Y kit further resolves the samples into seven groups. The Y filer kit adds five more loci, separating all but three samples with the most common type. Adding either DYS522 or DYS576 to the Yfiler loci resolves all 25 samples with the most common type. In this population set, 7 of the 20 additional Y-STRs have the same ability to resolve sample haplotypes as all 20 loci, which demonstrates promise for future multiplexing. These loci include DYS449, DYS505, DYS522, DYS532, DYS534, DYS570, and DYS576. Future studies will evaluate other YSTRs beyond these 37 loci, which may also be useful in Y-STR testing communities. 1 table and 7 references