The study analyzed the 608-bp hypervariable region 1 (HV1) sequences from 36 local dogs, in order to characterize the population genetic structure of canid mitochondrial DNA (mtDNA).
The findings show that outbred dogs cannot be reliably assigned to specific breed groups (as described by their owners) using mtDNA typing, but that the HV1 region in domestic dog mtDNA can provide discriminating information that is likely to be useful for exclusionary purposes. The authors recommend that forensic analysts rely primarily on information from the HV1 region in domestic dog mtDNA analysis for including or excluding an individual animal as a possible source of evidence in a criminal investigation. Despite the lack of genetic subdivision between the local and global dog populations, each population contained highly variable haplotypes. Estimates of haplotypic diversity based on local dog populations provide a more accurate picture of local mtDNA structure than samples of dogs combined from different and diverse origins. For casework, analysts should rely more on databases that use local samples, since they would be sufficient and perhaps a more relevant dataset in assessing the power of typing results in most forensic investigations. Buccal cells were taken from 58 domestic dogs by using Bucca-IAmp DNA Extraction Kit. Thirty-one samples were obtained from the University of California, Davis, Veterinary Genetics Laboratory, with the remaining 27 samples obtained from volunteers' dogs in northern and southern California. These samples consist mostly of mixed breed animals that represent 19 distinct breeds, consistent with the predominance of mixed breed dogs in the United States. A dog was characterized as pure-bred or of single-breed ancestry based on either the owner's account or the dogs' size and appearance. Detailed descriptions of the analytical methods are provided. 6 tables, 28 references, and appended Gen Bank sequences used in the study