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Submitted to: Encyclopedia of Animal Science
Publication Type: Other Publication Acceptance Date: 6/3/2004 Publication Date: 11/30/2004 Citation: Nonneman, D.J., Smith, T.P. 2004. Genetics: Molecular. Encyclopedia of Animal Science. p. 466-468. Interpretive Summary: Advances in molecular genetics have allowed better diagnosis and treatment of inherited diseases, a clearer understanding of the biological processes that dictate inherited traits, and identification and selection of superior animals. Traditionally, animal breeders have made genetic progress by selecting superior animals for breeding stock. Breeding goals may involve selection of a combination of desirable traits, and selection for multiple traits is usually counterproductive. The use of DNA markers for selection of specific traits would greatly benefit the accuracy and efficiency of breeding progress. The ultimate goal is to identify genes responsible for desirable traits and develop schemes that use this information to direct breeding decisions and maximize profitability. The application of molecular genetics to the selection of superior animals used for production shows promise for traits affecting meat quality and production, reproductive efficiency and disease resistance as we develop faster and more accurate ways to integrate individual animal variation and knowledge of livestock genomes. Technical Abstract: Advances in molecular genetics have allowed better diagnosis and treatment of inherited diseases, a clearer understanding of the biological processes that dictate inherited traits, and identification and selection of superior animals. Traditionally, animal breeders have made genetic progress by using phenotypic information on available animals for selection of breeding stock. Breeding goals may involve selection for a combination of traits, and mass selection for these traits is usually counterproductive. Experimental and statistical methods have been developed to separate environmental from genetic effects to better define quantitative traits and their genomic position or QTL. The ultimate goal is to identify chromosomal regions or genes underlying polygenic traits and develop schemes that use this information to direct breeding decisions and maximize profitability. Since the development of high-resolution genetic maps, several instances of causal genetic variation or mutations in livestock that alter phenotype have been identified at the molecular level. The identification and characterization of double-muscling in cattle and Rendement Napole (RN) in swine are two classic examples of molecular genetic successes in livestock. Further investigation reveals that additional alleles of these genes involved in major mutations have a significant effect on quantitative trait variation in livestock. The application of molecular genetics to the selection of superior animals used for production shows promise for traits affecting meat quality and production, reproductive efficiency and disease resistance as we develop faster and more accurate ways to integrate phenotype and genotype with further development of genetic maps, molecular resources, and knowledge of livestock genomes. |
