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United States Department of Agriculture

Agricultural Research Service

Title: Molecular Approaches to Genetic Improvement

Author
item Thallman, Richard

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: December 1, 2004
Publication Date: May 1, 2005
Citation: Thallman, R.M. 2003. Molecular approaches to genetic improvement [proceedings]. Genetic Prediction Conference Workshop, December 6, p. 5-15.

Interpretive Summary: The benefits of genetic testing and its expected impact on genetic improvement of beef cattle are discussed. Three general types of DNA tests (linked markers, functional tests, and association tests) are each described and their relative advantages and disadvantages are outlined. For the immediate future, association tests based on single nucleotide polymorphisms (SNP) are likely to have the most impact in beef cattle breeding. Conversion of quantitative trait loci (QTL) into association tests is a more efficient use of resources than conversion of association tests into functional tests. Challenges in the application of association tests based on multiple SNP are described, using two SNP in the mu-calpain gene as an example. The importance of accounting for breed and pedigree effects when testing associations between polymorphisms and phenotypes is illustrated. There is a need for the development of high-throughput systems for converting QTL into association tests and for a new generation of resource populations in which to develop and evaluate association tests. The application of DNA testing is not as simple as it first appears, but the potential benefits are enormous. It will eventually become widespread in cattle breeding, and perhaps, in cattle management.

Technical Abstract: The benefits of genetic testing and its expected impact on genetic improvement of beef cattle are discussed. Three general types of DNA tests (linked markers, functional tests, and association tests) are each described and their relative advantages and disadvantages are outlined. For the immediate future, association tests based on single nucleotide polymorphisms (SNP) are likely to have the most impact in beef cattle breeding. Conversion of quantitative trait loci (QTL) into association tests is a more efficient use of resources than conversion of association tests into functional tests. Challenges in the application of association tests based on multiple SNP are described, using two SNP in the mu-calpain gene as an example. The importance of accounting for breed and pedigree effects when testing associations between polymorphisms and phenotypes is illustrated. There is a need for the development of high-throughput systems for converting QTL into association tests and for a new generation of resource populations in which to develop and evaluate association tests. The application of DNA testing is not as simple as it first appears, but the potential benefits are enormous. It will eventually become widespread in cattle breeding, and perhaps, in cattle management.

Last Modified: 10/22/2014
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