Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 6, 2004
Publication Date: N/A
Interpretive Summary: Meeting Abstract, no interpretive summary required.
Technical Abstract: The development of genetic maps for domestic species and their use for identifying chromosomal regions that harbor genes affecting economically important traits has been the focus of livestock genomic research. Variation within genes having a major impact on the phenotype of the animal, like the form of myostatin that causes double-muscling in cattle, have been identified, but most loci influencing quantitative traits remain unknown. Regions in the genetic material that harbor genes influencing economically important traits are known as quantitative trait loci (QTL). Their approximate locations in the genome and the proportions of variation in the trait that they explain have been estimated. Traits that are sex limited, have low heritability, that are expensive to measure, or that need to be measured in the carcass are best suited for improvement using genomic approaches. Such is the case for carcass composition and meat quality traits, including meat tenderness. Variation in meat tenderness has significant impact on beef consumer's satisfaction, but classical selection techniques have not been effective in eliminating the fraction of animals yielding undesirable palatability traits. Establishing the genetic basis for variation in meat tenderness would likely aid in the development of selection criteria for improving this trait in cattle. Quantitative trait loci associated with the expression of meat tenderness have been identified. A gene known to be involved in postmortem proteolysis resides within the boundaries of a QTL located on chromosome 29. The micromolar calcium-activated neutral protease (CAPN1) gene encodes a cysteine protease, µ-calpain, that degrades myofibrillar proteins under postmortem conditions. Genetic markers, known as single nucleotide polymorphisms (SNP), have been developed in the gene. These genetic markers have been associated with meat tenderness in beef cattle. Their association has been assessed in several cattle populations. Breed evaluations in the future could include genetic marker information to determine the breeding value of the animals with a higher accuracy.