In this study, massively parallel sequencing (MPS) technology was used to sequence 28 forensically relevant Y-chromosome STRs in a set of 41 DNA samples from the three major U.S. population groups (African Americans, Caucasians, and Hispanics).
Massively parallel sequencing (MPS) technology can determine the sizes of short tandem repeat (STR) alleles, as well as their individual nucleotide sequences. Thus, single nucleotide polymorphisms (SNPs) within the repeat regions of STRs and variations in the pattern of repeat units in a given repeat motif can be used to differentiate alleles of the same length. In the current study, the resulting sequence data, which were analyzed with STRait Razor v2.0, revealed 37 unique allele sequence variants that had not been previously reported. Of these, 19 sequences were variations of documented sequences resulting from the presence of intra-repeat SNPs or alternative repeat unit patterns. Despite a limited sampling, two of the most frequently observed variants were found only in African American samples. The remaining 18 variants represented allele sequences for which there were no published data with which to compare. These findings illustrate the potential of MPS for increasing the resolving power of STR typing and emphasize the need for sample population characterization of STR alleles. 2 tables, 1 figure, and 19 references (publisher abstract modified)