Genetic and genomic technologies from A-Z

For many years, genetic improvement in swine herds was traditionally made by small breeders. Beginning in the last half of the 20 century, following the lead of corn hybrid companies, breeding companies and larger seedstock breeders moved to improve swine by employing stringent selection methods, developing specialized sire and dam lines and then synthetic lines to be sold to customers as commercial products. Fat reduction and increased growth rates were significant but gains in reproduction and feed efficiency were more limiting and meat quality generally declined. Beginning in the early 1990s advances in the fields of molecular genetics began to provide additional tools for further improvements. Several recent quantitative trait loci (QTL) scans and candidate gene analyses have identified important chromosomal regions and individual genes associated with traits of economic interest including growth and fat levels, meat quality traits, reproduction and disease resistance. Commercial genetic companies are actively using this information combined with traditional performance information to improve pig production by marker assisted selection (MAS). Completion of the sequencing of the pig genome, coupled with development of large single nucleotide polymorphism (SNP) panels offers the possibility of whole genome association trials and genomic selection which is likely to provide the ability to select animals for traits previously difficult to improve. Such genetic improvement will improve production characteristics and provide healthier food products worldwide. The purpose of this paper is to help breeders understand the technologies and see how they fit in their programs.