Comprehensive coverage of human last meal components revealed by a forensic DNA metabarcoding approach

Abstract

Stomach content analyses are a valuable tool in human forensic science to interpret perimortem events. While the identifcation of food components of plant and animal origin has traditionally been conducted by macro- and microscopical approaches in case of incomplete digestion, molecular methods provide the potential to increase sensitivity and taxonomic resolution. In particular, DNA metabarcoding (PCR-amplifcation and next generation sequencing of complex DNA mixtures) has seen a rapid growth in the feld of wildlife ecology to assess species’ diets from faecal and gastric samples. Despite clear advantages, molecular approaches have not yet been established in routine human forensics to investigate the last meal components of deceased persons. In this pilot study we applied for the frst time a DNA metabarcoding approach to assess both plant and vertebrate components of 48 human stomach content samples taken during medicolegal autopsies. We obtained a fnal dataset with 34 vertebrate and 124 vegetal unique sequences, that were clustered to 9 and 33 operational taxonomic units (OTUs), respectively. Our results suggest that this approach can provide crucial information about circumstances preceding death, and open promising perspectives for biomedical dietary surveys based on digested food items found in the gastrointestinal tract.