Molecular genetics is an additional tool which provides information for the detection and exploitation of genes or chromosomal regions with large influence on economic traits. This comes from the development of dense maps of linkage disequilibrium among genetic markers for many livestock species. Although each type of genetic marker has advantages and disadvantages, the only polymorphisms with enough density to meet important requirements for gene mapping are the Single Nucleotide Polymorphisms (SNP). They allow identifying and studying genes that influence traits of interest and enable new alternatives for genetic evaluation and selection, as in the case of genomic selection, whose implementation for different species of livestock makes up the main objective of this project. Initially, dairy and beef cattle, sheep and goats are being studied.