4.11.1 Indicator traits under development (2024)

However, for some breeding goal traits, indicator traits are still subject of research projects. For example: resistance to disease is a trait that becomes visible after infection often at an unpredictable moment. In fish, challenge tests are performed on full- and half sibs to establish genetic resistance of a fish family. From an ethical point of view this is not desirable. Nowadays, the results of the challenge tests are used to compose a reference population for genomic selection. This gives the opportunity to restrict the challenge test to a limited amount of animals. In pigs organoids are used to study complex phenotypes. An organoid is a miniaturized and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural and biological complexity of that organ. The intestinal tract and the immune system are prioritized for this type of research. The pathway between functional DNA and its phenotypic expression is used to give insight in complex breeding goal traits and how to translate that into breeding strategies. This type of research may lead to indicator traits for breeding goal traits. If worthwhile, organoid results will be used to compose reference populations used in genomic selection to improve the complex breeding goal trait.