Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/15/2005
Publication Date: 11/13/2005
Citation: Nonneman, D.J. 2005. Development of populations for identifying quantitative trait loci (QTL) in swine. Morelos, Mexico. 11/13-19/2005. IN: Proceedings, XLI National Livestock Research Meeting. Interpretive Summary: The use of molecular markers offers a great potential to improve efficiency of animal breeding. Development of cost effective techniques and their integration into production systems is the challenge. Techniques to isolate and evaluate DNA have revolutionized our understanding of, and ability to regulate, the biological processes that are involved in the development of economically important traits. Development of new technology to increase the efficiency of livestock production and benefit consumers is the challenge. With this objective, a program has been developed at MARC to identify the chromosomal regions where genes influencing growth, carcass composition, and meat quality traits reside. Characterizing the variation of these regions using outbred populations currently being developed on-center will be done. Novel marker systems for high throughput genotyping need to be developed to allow this characterization. The purpose is to use genomic information in either, functional genomics studies or in marker-assisted selection to improve the efficiency in animal breeding schemes.
Technical Abstract: With changing consumer preferences and market demands for meat products in the last few decades, livestock producers frequently need to quickly change selection targets and strategies to remain competitive. Traditional selection methods generally take several generations of selective breeding before substantial improvements are realized in the herd. Therefore, many theoretical studies have been done over the past few decades to incorporate molecular genetic information in selection programs. This requires the development and validation of genetic markers that are predictive of traits targeted for selection. The first step to developing markers with predictive value is to scan the genome for locations that are significantly associated with performance traits of economic interest. This scan is often conducted in a structured population developed from a cross of breeds that are divergent for the traits of interest. The next step is to re-evaluate the genomic region in a separate set of animals to verify that the QTL actually exists. The first resource populations tried to maximize the number of important traits that could be studied in one population. Therefore some of the first populations included Meishan pigs as they were quite different from US pigs for most production traits, specifically, growth rate, body composition and a number of reproduction related measurements. Later, resource populations were developed with commercially relevant germplasm.