Genomic selection is a modern tool used in animal breeding, based on information from tens of thousands of markers associated with genes that influence animal production. The advantage of using the study of DNA or genetic markers is that it is possible to know if an animal has genes in its genome that influence the development of a certain characteristic important for the production or health of the animal. Thus, it is possible to obtain: a significant increase in the selection intensity and of the selection precision; significant decrease in the value of the intergenerational interval, doubling the genetic progress that can be achieved with each generation. Genomic selection can help breeders identify individuals with higher breeding values as early as possible. Genomic selection or molecular marker-assisted selection also helps us to quickly eliminate pathogenic genes or those that negatively influence economically important traits from the population. Selection assisted by molecular markers also has the advantage of facilitating the very rapid introduction of an important gene or group of genes into the genome of a population, a procedure called gene introgression in the population, achievable in a maximum of 2-3 generations. An example of the use of introgression may be the bringing of the gene responsible for resistance to certain diseases from a natural donor breed to a breed with very good production.