Validation of the AMPFlSTR (R) SGM Plus (TM) system for use in forensic casework

The AMPFlSTR(R) SGM Plus(TM) system is a commercially available STR multipl ex produced by Applied Biosystems, a division of Perkin Elmer, Foster City, California, USA that supersedes SGM. The multiplex contains the six SGM lo ci, amelogenin and four additional loci. These additional loci are D3S1358, D19S433, D16S539 and D2S1338. Consequently, the match probability is signi ficantly improved (conservatively quoted as 1 in 10(9) for reporting a full profile match). The system was subjected to validation. For example, agein g and degradation studies demonstrated semen stains to be the most stable e vidence type, whereas buccal scrapes were the least stable. An apparent ris e in the sensitivity increases the chance of obtaining successful results f rom the more difficult samples submitted for analysis. Two of the new loci (D3S1358 and D19S433) are low molecular weight (between 100 and 150 base pa irs); this improved the success rates of the degraded samples where high mo lecular weight loci may drop out. Of 26 non-primates tested, four gave resu lts that appeared as single peaks and were unlikely to cause interpretation problems. None of the 19 micro-organisms tested gave discernible results. Extensive casework and simulated casework studies demonstrated that SGM and SGM plus results were comparable. There was one example of a null allele ( primer binding site mutation) recorded at the HUMFIBRA locus (in both syste ms). However, a concordance study of 1000 samples using both SGM and SGM pl us did not demonstrate any differences in typing. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.