Key points:
- Human DNA can be transferred and collected from dogs.
- Although researchers were able to recover human DNA from all areas of the dogs, some areas consistently provided more DNA than others.
- The positive study results expand opportunities for DNA to assist in criminal investigations.
Dogs are often used for tracking in police investigations, but forensic scientists at Flinders University (Australia) say dogs can provide even more crucial evidence—including DNA. The team’s new study sheds light on the presence and transfer of human DNA on dogs, possibility expanding opportunities for DNA to assist in criminal investigations.
For the study, researchers collected human DNA from 20 pet dogs of various breeds from multiple households by swabbing six areas on the dog— the chest, top of the head, back, left and right sides and stomach.
According to the results, published in Genes, human DNA was successfully retrieved from all areas of the dogs, although some areas consistently provided more DNA than others, such as the head and back. Interestingly, the samples collected from the left side of the dogs were taken from deeper in the fur and closer to the skin. Therefore, the study authors theorize that DNA collected by dogs is retained on the surface of the fur rather than being embedded under it. Overall, higher quantities of DNA were recovered from the back, head, and right side of the dogs.
In a second part of the study, a researcher patted and scratched each participating dog under the neck/chin area with a single bare hand to determine if their DNA could be transferred and detected on a dog during a single contact event. Of the 20 DNA swabs collected, analysis showed 10 contained DNA of the individual that pet the dog.
"This information may assist those investigating criminal acts in which dogs are involved to consider situations [where] it may be useful to sample for human DNA from a dog,” the researchers conclude in their paper. "[The study] also showed that investigators may need to consider dogs as a vector for indirect transfer of human DNA within particular scenarios."