Evaluating 7.5 M Ammonium Acetate for the Extraction of DNA from Degraded Saliva Samples: A Comprehensive Forensic Evaluation

Abstract

Recovering DNA from environmentally degraded biological samples remains one of the most persistent challenges in forensic science. Saliva, though highly valuable as a source of epithelial cells, is frequently exposed to detrimental environmental factors that accelerate chemical, enzymatic, and structural DNA degradation. This study thoroughly investigates the effectiveness of a 7.5 M ammonium acetate-based extraction protocol for the recovery of usable DNA from saliva subjected to controlled UV radiation, thermal degradation, and sodium hypochlorite exposure. DNA yield and purity were assessed using NanoDrop spectrophotometry, and STR profiling was performed using the VeriFiler™ Express PCR Amplification Kit. Results demonstrated that although degradation significantly impacted nucleic acid concentration and purity, amplifiable DNA was recovered, producing partial to near-complete STR profiles. These findings indicate that ammonium acetate precipitation is a cost-effective, non-toxic alternative for resource-limited laboratories, with important implications for forensic casework involving compromised biological evidence.