Forensic mtDNA hair analysis excludes a dog from having caused a traffic accident

A dog was suspected of having caused a traffic accident. Three hair fragments were recovered from the damaged car and subjected to DNA sequence analysis of the canine mitochondrial D-loop control region. The results were compared to saliva and hair samples from the alleged dog, as well as to control hair samples from four unrelated dogs of different breeds. Two sequence types exhibiting five nucleotide differences in a 377 bp fragment were identified among the four controls. Whereas the evidence hair fragment was identical to the type 1 control sequence, the alleged dog shared the type 2 control sequence except for one position. Thus the dog could be excluded as the origin of the hair fragment. As canine mtDNA appears to exhibit only limited polymorphism, mitochondrial D-loop sequence comparison is currently only suitable for exclusions.