Developing a canine genetic testing program at the Atlantic Veterinary College: pilot study on disease susceptibility loci in Labrador retrievers

Canine genetic testing for disease susceptibility loci provides invaluable guidance for dog breeders, enabling them to eliminate known disease carriers from breeding programs, and thereby avoid generating affected progeny. Despite the recognized risks associated with breeding dogs of unknown genotypes, many breeders forgo genetic testing due to prohibitively high costs and long turnaround times associated with these tests. Our overall objective was to develop and validate a rapid turnover, cost-effective canine genetic testing program at the Atlantic Veterinary College (AVC). To this end, we conducted a pilot study to develop and validate a complete genetic test panel for heritable diseases in Labrador retrievers, including (1) exercise-induced collapse, (2) progressive rod-cone degeneration, and (3) degenerative myelopathy, which are each associated with a single nucleotide polymorphism (SNP) at the disease locus, and (4) centronuclear myopathy which is associated with a short interspersed nuclear element (SINE) insertion. First, plasmids were designed containing wild type or mutant alleles of each gene of interest and served as genotyping controls. Next, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based tests were designed for SNP and SINE typing. Following PCR-RFLP test optimization with plasmid DNA controls, approximately 300 canine buccal swabs obtained from Labrador retriever breeders were tested. Our blinded test results were validated by comparing our test results with results previously obtained by breeders. Our results corresponded 94-98% to the genotype status for the four genetic tests and 100% to the disease statuses of the dogs. Pending final validation, we will be able to offer these tests at the AVC. Ultimately, results from this study will support a grant application to develop a full genetic testing program.