Science links variations in DNA patterns to certain animal characteristics. By mapping the differences between the DNA of animals that possess a particular characteristic and those that do not, it can be determined in which gene and at what position in the gene a mutation has occurred that causes this characteristic. By comparing the external characteristics with variation in DNA, a reliable diagnostic test can be validated. This generally results in publication of an article in a peer-reviewed scientific journal. These articles are often based on a single breed.
DNA tests for these external characteristics offer countless possibilities and applications for breeders. Some examples are DNA tests for coat colours (various animal species), horn/polled, milk proteins (cattle), meat characteristics and susceptibility to E. coli (pig), susceptibility to scrapie (sheep), hairlength (cat and dog), sex determination (e.g. birds, hyenas, capybaras, anteaters and sloths) and quality gene (pigeon). The availability of these DNA tests enables breeders to use this knowledge and these DNA tests to improve the quality of a population or breed.

Mutations that have been described and validated in one breed can also be present in other breeds. Very often, that fact is not published in additional scientific articles. The presence of these mutations in other breeds is determined by service laboratories that perform the DNA-tests. Determining how reliable a certain DNA-test is for a certain breed is no easy task. On our website, we indicate that a test is suited for a particular breed only if it is published or because it has been determined by a service laboratory. It is up to the owner to decide whether he or she would like to have a test performed based on the criteria set out above.