Unearthing forensic genetics: preliminary results on the ability to generate DNA profiles from buried human biological samples.

Burying objects with biological material is a common procedure in many crimes, intending to hide and/or accelerate the process of degradation of the possible biological information they may contain. In this sense, the central question of this preliminary study concerns investigating the impact of a burial process on the degradation of genetic material, specifically on blood and saliva samples, compared to the same type of samples deposited on the surface. Saliva and blood samples were methodically positioned on a white cotton T-shirt, with half of the samples being buried and the other half placed on the surface of the soil within the same quadrant of the box. The degradation was analysed using two complementary approaches: genetic material quantification and genetic profile analysis of autosomal markers, considering also physicochemical factors such as humidity, temperature, and pH. Preliminary results indicate a significant interaction between time, sample location, and sample type in driving genetic loss. Notably, a significant, irreversible loss of genetic material was observed within an average of five weeks for both sample types when buried. Despite the preliminary nature of these findings due to the absence of experimental replicates, they provide a critical forensic baseline for estimating the viable window for DNA profiling in buried evidence.