The journey of my dog’s sample in the genetic lab. Step 3
Interpretation and use of genetic test results
Understanding and correct interpretation of a genetic test result is one of the most important steps in using a genetic test for dog breeding. As we have written in previous blog posts, several steps are important in performing a genetic test: sampling, DNA isolation, test performance, and interpretation of results. With correct interpretation of the genetic test results, we can contribute a lot to the positive development of an individual breed, and we can even improve it.
Genetic tests are a very powerful tool used in dog selection. Their improper use or misunderstanding can also lead to negative impacts on an individual breed. By recklessly eliminating animals from breeding, we can reduce the genetic diversity of an individual breed, which can lead to various health problems. To avoid problems, it is necessary to understand some of the properties of genetic tests.
Genetic tests are used to analyse specific DNA changes called mutations. It is very important to know what the tested mutation is causing. Mutations can cause loss of basic body functions and consequently genetic diseases, increase the risk of genetic disease, affect the body's response to the application of specific drugs (pharmacogenetics), affect the dog's physical characteristics, colour and quality of the coat. Genetic tests are in most cases specific to individual dog breeds. When choosing a genetic test, it is therefore necessary to pay attention to the breed of animal and the trait we want to test.
To interpret genetic test results, it is very important to know the mode of inheritance of the tested mutation. You can find this information on our website in the description of individual genetic test and on the genetic test report. You can read more details about the modes of inheritance HERE.
Until recently, genetic tests were only available for monogenic diseases where only one gene is involved in the development of the disease. With the improvement of technology and a better understanding of the canine genome, tests for polygenic diseases have been developed. Polygenic diseases are associated with several different genes. Interpretation of the results is particularly demanding, as more association studies are necessary to determine the connection between different mutations and the phenotype. With a poor knowledge about the basic laws of genetics the use of polygenic genetic tests can be quite demanding.
When choosing a genetic test as well as when interpreting the results, it is good to know in which breeds the tested mutation occurs, what is its frequency in the population and what is its penetration. The frequency of a mutation is sometimes difficult to determine, as it can vary by breed as well as between dog populations. Penetration tells us the proportion of animals with the mutation that develop the disease. Many monogenic genetic diseases have 100% penetration, which means that each animal with this mutation will develop a specific genetic disease. However, there are also mutations that do not have 100% penetration. In such cases, only some animals develop a specific genetic disease. All the above characteristics of genetic tests must be considered in breeding decisions.
With a basic knowledge of genetic laws, correct use of genetic tests and correct interpretation of results, breeders can improve the quality of life for many pets, and often make it easier for new owners to choose a healthy dog that best suits them.