FORENSIC APPLICATIONS OF A RAPID, SENSITIVE, AND PRECISE MULTIPLEX ANALYSIS OF THE 4 SHORT TANDEM REPEAT LOCI HUMVWF31/A, HUMTH01, HUMF13A1, AND HUMFES/FPS

A system of four short tandem repeat loci (HUMVWF31A, HUMTH01, HUMF13A1, and HUMFES/FPS) has been tested in co-amplification with forensic (post-mortem and post-coital) DNA samples. Semiautomated DNA typing was employed to analyze polymerase chain reaction (PCR) products formed by extension of primers labeled with a fluorescent dye at the 5'-terminus. Most DNA extracts could be typed, although a few required the addition of bovine serum albumin or a pretreatment by ultrafiltration in order to obtain sufficient signal for typing. Balanced signals for the alleles were obtained frequently across the loci, although preferential amplification of HUMTH01 was observed often with the forensic samples. Band splitting due to nontemplate nucleotide addition to the blunt ends of the amplimers was frequently detected for the DNA extracted from the forensic samples. A database was constructed for the African-American population and compared with a Caucasian database. Few differences were observed across the two populations, except at the locus HUMTH01. The fluorescence-based system facilitates large-scale databasing, because the PCR products run off the gel, allowing more than one set of samples to be analyzed per run. Polyacrylamide gel reuse did not diminish genotyping accuracy.