Genetic disorders pose significant challenges for dog welfare, veterinary medicine, and responsible breeding. Until recently, knowledge about the frequency of disease-associated genetic variants across breeds was limited. Donner et al. (2018) conducted the largest canine population screening to date, analyzing DNA from more than 83,000 mixed-breed and 18,000 purebred dogs representing 330 breeds. The study tested for 152 known variants associated with inherited disorders using a custom-designed microarray.
The results were striking: approximately 40% of dogs carried at least one copy of a tested disease variant. Many variants were found in both mixed and purebred populations, suggesting a shared genetic heritage. However, mixed-breed dogs were more likely to be carriers of common recessive diseases, while purebreds were more often genetically affected by them. This provides DNA-based evidence for hybrid vigor, where genetic diversity may protect against certain inherited disorders.
The study also discovered 22 disease variants in breeds where they had not previously been documented, underscoring the importance of continued genetic monitoring. Furthermore, the creation of MyBreedData (www.mybreeddata.com) provided a public resource to track prevalence of inherited disorders across breeds.
These findings highlight the importance of genetic screening in veterinary practice and breeding programs. Identifying carriers and affected individuals can guide responsible mating choices, reduce disease prevalence, and improve long-term canine welfare. The research emphasizes that while selective breeding has produced distinct breeds, it has also concentrated certain health risks, making broad genetic surveillance a vital tool for the future of dog health management.
Source: Donner, J., Anderson, H., Davison, S., Hughes, A. M., Bouirmane, J., Lindqvist, J., Lytle, K. M., Ganesan, B., Ottka, C., Ruotanen, P., Kaukonen, M., Forman, O., Fretwell, N., Cole, C., & Lohi, H. (2018). Frequency and distribution of 152 genetic disease variants in over 100,000 mixed breed and purebred dogs. PLoS Genetics, 14. Published April 1, 2018.
