Recent innovations and tools of molecular genetics applied to animal breeding for the improvement of animal productions

Traditionally, animal breeding improved production traits by using the performance of livestock animals, and including the performance of the ancestors and/or siblings of the animal to estimate the genetic component of the performance to select the best parents to produce the next generation. It has long been recognized that variation at the genomic level was responsible for the observed variation in the traits. With the onset of the genomics era the number of livestock species with a known genome sequence rapidly increases. Thus, the tools to investigate the biological background of variation in the production traits and the use of this information to speed up genetic improvement of production of livestock became available. During the last decade the research on the regulation of production traits and new traits (e.g. animal health) has resulted in new insights and has developed several new tools that can be used by the breeding companies. The regulation of many production traits proved to be highly complex. As expected genetic variation in the coding sequences of the genes was found to be important. However, a number of other mechanisms were also recognized as important regulators determining the production. Among these are the regulation of the expression of the genes at several levels. A first regulatory level is the epigenetic level – chemical changes made to the chromosomes to make active or inactive areas, directly affecting gene activity. Once a gene is expressed the resulting mRNA can be inactivated, or translated into proteins. These proteins are important as building blocks for the body of the animal and for the livestock product. The activities of the proteins are important for producing the metabolites determining the quality of the products. New omics technologies have been developed to measure all these levels of expression of the genome and develop new tools to improve livestock production. During the presentation we will explain the new tools and show results that can be used by the breeding industry. At present, some of these results are already actively used by the breeding industries, and we will indicate how the new tools are used.