The contribution of seawater in DNA degradation: Comparison of genetic results from skeletal remains affected by different taphonomic conditions in forensic contexts

In the field of forensic genetics, the examination of compromised biological samples is a common investigative challenge. It is crucial to thoroughly assess the thanatological and taphonomic events affecting human samples for genetic analysis, including the environment surrounding the corpses or the skeletal remains, which, in the present cases, is represented by seawater. This study aims to compare different conditions to determine the extent to which cadaveric submersion in seawater affects endogenous DNA, by evaluating the degree of degradation and nucleic acid quantity. The samples selected consist of skeletal remains exposed to the marine environment and belonging to two different scenarios. The first context is characterized by a long-term submersion period, while the second involves bones exposed for a short-term period and unexposed ones. The analytical workflow on these remains includes pretreatment, DNA extraction, quantification, STR amplification and fragments analysis. The results from the two scenarios were compared through statistical evaluation. It was possible to determine significant differences between the group of bones exposed to the water for an extended period and the two groups of samples originating from the second context. This highlights that prolonged submersion in seawater had preservative effects on the endogenous DNA.