Canine-specific STR typing of saliva traces on dog bite wounds

Abstract

Forensic investigations in dog attacks usually involve the examination of bite marks and toothprints, the dog's stomach and pathological methods. For identification of the offending dog we evaluated canine STR typing of saliva traces on dog bite marks. The specificity of 15 canine-specific STRs was tested on human-canine DNA mixtures prior to an applied study in which 52 cases of dog bites were investigated. The first-aid wound bandages as well as swab samples from the surrounding area of the wound were used for DNA analyses. Generally, it was possible to obtain a canine-specific STR profile from the dog's saliva left on the wound area, even when high background of human DNA was present (blood). Interestingly, we found canine STR typing to be more successful when the bandages and swabs showed high amounts of human blood, i.e. when the dog bite was severe. Canine saliva was then sometimes visible as white-coloured secretion on the human blood surface. Less severe bite cases, which did not result in bleeding wounds, showed less success in obtaining useful STR results, probably due to the fact that the surface of the wounds may have been treated before the victims consulted medical aid which therefore removed the canine cells.

Recommendations for animal DNA forensic and identity testing

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Low-volume amplification on chemically structured chips using the PowerPlex16 DNA amplification kit

“…DNA analysis has become an indispensable tool in almost every forensic laboratory and is an integral part of main forensic tasks (i.e., paternity testing, human and nonhuman identification, and examination of forensic stains) [1][2][3][4][5][6]. The application of polymerase-based amplification of DNA-and especially of autosomal short tandem repeats (STRs)-to forensic molecular genetics has been pathbreaking [7][8][9][10].…”

Developmental Validation of Short Tandem Repeat Reagent Kit for Forensic DNA Profiling of Canine Biological Materials

“…Shed dog hairs can be transferred among individuals involved in a crime and can link a suspect to a crime scene, a suspect to a victim, or a victim to a crime scene (4,5). Dog evidence can also be used in dog attack cases and abuse cases (6).…”