Evidence is growing that we will be successful in identifying markers with proximity to loci having substantial effect on economically important traits. For instance, in plants , several QTLs have been identified and markers implemented through MAS to improve disease resistance and drought tolerance in breeding programs . Markers for several debilitating human diseases have been discovered and are used for genetic screening and parental identification purposes. Recently, a region on pig chromosome 4 was shown to contribute to breed difference in growth rate, fatness and length of the small intestine. A region on cattle chromosome 1 may contain genes responsible for "polledness." Information will soon be released detailing the identification of markers flanking QTLs responsible for milk component and yield variation within elite dairy families. Based on these discoveries, and those that are sure to follow, it is reasonable to assume that MAS for economically important traits will be implemented in both beef and dairy cattle selection programs in the very near future.