Presence of Human DNA on Household Dogs and Its Bi-Directional Transfer

Abstract

Awareness of the factors surrounding the transfer of DNA from a person, item, or surface to another person, item, or surface is highly relevant during investigations of alleged criminal activity. Animals in domestic environments could be a victim, offender, or innocent party associated with a crime. There is, however, very limited knowledge of human DNA transfer, persistence, prevalence, and recovery (DNA TPPR) associated with domestic animals. This pilot study aimed to improve our understanding of DNA TPPR associated with domestic dogs by collecting and analysing samples from various external areas of dogs of various breeds, interactions with humans, and living arrangements, and conducting a series of tests to investigate the possibility of dogs being vectors for the indirect transfer of human DNA. Reference DNA profiles from the dog owners and others living in the same residence were acquired to assist interpretation of the findings. The findings show that human DNA is prevalent on dogs, and in the majority of samples, two-person mixtures are present. Dogs were also found to be vectors for the transfer of human DNA, with DNA transferred from the dog to a gloved hand during patting and a sheet while walking.

Indirect DNA Transfer and Forensic Implications: A Literature Review

“…Similarly, Reither et al [67] investigated two possible scenarios, demonstrating that an indirect DNA transfer could occur from clothing to flooring and from flooring to clothing in both 'active' and 'passive' situations, even if the DNA transfer was greater in active simulation. Interestingly, Monkman et al [70] demonstrated that a domestic animal (in their experimental model they used a dog) could be a vector for human DNA transfer, demonstrating a transfer from the animal to a gloved hand during patting and a bed sheet while walking.…”