Validation and Casework Testing of the BioPlex-11 for STR Typing of Telogen Hair Roots

The study developed a new STR typing strategy, BioPlex-11, for analyzing telogen hair roots, which often contain limited or degraded DNA. This method allowed simultaneous amplification and analysis of 11 polymorphic systems with amplicon sizes smaller than 270 bp, including six STR loci from the European standard set and four additional robust STR systems, plus the sex-specific locus amelogenin. The multiplex system was designed to improve forensic casework by enabling DNA typing from highly fragmented samples, such as telogen hairs, which typically result in weak signals with larger STR fragments. The study involved testing with human control DNA and blood samples from 15 donors, demonstrating high specificity and reproducibility with only 0.4% drop-out alleles observed. This approach aimed to enhance the efficiency and success of DNA profiling in forensic investigations.