Two caseworks for one gene: successful species identification from compromised bone materials with the 12S rRNA

Abstract

The availability of a reliable molecular assay in species recognition in forensic cases is of paramount importance when visual inspection or morphological methods are not exhaustive, especially from challenging samples. Here, two different caseworks involving bone samples founded during medico-legal outdoor investigations are presented. In order to exclude the human nature of the specimens and to determine the exact species they belong to, we proceeded with the molecular approach trying to generate sequences from the classical mtDNA markers cyt b and COI. However, they both gave critical results. For this reason, a short amplicon of ~ 150 bp of the 12S rRNA gene was used as an alternative.This short fragment was sufficient to identify the biological origin of the bone specimens with a high degree of certainty leading to the exclusion of their human nature. This work highlights the utility of the 12S rRNA and underlines the importance of deepen the choice of alternative shorter markers with respect to the classical ones, in order to achieve species identification even from challenging and degraded material in forensic criminal and wildlife caseworks.

Keywords: 12S rRNA; DNA barcoding; Degraded DNA; Mitochondrial DNA; Skeletal remains; Species identification.