Abstract
Stomach content analyses are a valuable tool in human forensic science to interpret perimortem events. While the identification 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-amplification and next generation sequencing of complex DNA mixtures) has seen a rapid growth in the field 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 first 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 final 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.
Highlights
Stomach content analyses are a valuable tool in human forensic science to interpret perimortem events
The few studies published to date focused on the identification of a single taxon or food items using amplified fragment length polymorphism (AFLP) a nalysis[21,22] or PCR followed by Sanger s equencing[23,24]
The relative read abundance (RRA) of animal and plant items is summarised per assay for all samples combined (Fig. 1)
Summary
Stomach content analyses are a valuable tool in human forensic science to interpret perimortem events. 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 first time a DNA metabarcoding approach to assess both plant and vertebrate components of 48 human stomach content samples taken during medicolegal autopsies. DNA metabarcoding studies of stomach content samples have already been done to assess the diet of wildlife taxa such diverse as e.g. k rill[14], Norwegian lemmings[15], Antarctic toothfish16, spiders[17], Pygmy devil r ays[18] and b ugs[19] Despite their clear advantages, molecular approaches have surprisingly not yet been established in routine human forensics to comprehensively investigate the last meal components of deceased persons (but see[20] in a very different context). The use of solid or structural intact particles as a source of DNA is not always possible when dealing with (partially) digested stomach contents
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