By Casey R. Carl, DVM and Blake Blake Ballif, PhD
A topic in veterinary genetic testing currently getting significant attention is the difference between direct and indirect genetic testing for mutations associated with various diseases and traits. Although both types of testing can play a useful role in determining a dog’s genetic health status, the use of indirect genetic testing comes with some additional caveats that need to be considered when selecting the best testing strategy for a particular dog.
Direct Genetic Testing
As the name indicates, direct genetic testing is a general term for any genetic testing technique which looks for the presence of the specific genetic variant (mutation) known to play a causal role in a particular disease or trait. Therefore, regardless of which genotyping technique used, test results obtained from direct testing identify the presence or absence of the specific mutation that has been associated with the disease or trait. Barring differences in quality of laboratory practices and test development, direct testing is therefore the ideal method to detect a specific mutation. Furthermore, identifying the precise causative mutation in a DNA sample from a dog allows one to draw appropriate conclusions about the implications of this mutation ...