Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 28, 2000
Publication Date: April 3, 2001
Citation: Casas, E., Stone, R.T., Keele, J.W., Shackelford, S.D., Kappes, S.M., Koohmaraie, M. 2001. A comprehensive search for quantitative trait loci affecting growth and carcass composition of cattle segregating alternative forms of myostatin. Journal of Animal Science. 79:854-860. Interpretive Summary: A gene called myostatin has been shown to increase meat yield and decrease fat in cattle. These characteristics are also influenced by other genes. The objective of the present study was to identify the location of additional genes with moderate effect on growth and carcass traits in cattle with or without the form of myostatin that produces increase in meat tyield and decrease in fat. Seven different chromosomes were detected as having genes affecting these traits. Five of these locations influenced more than one trait. Genes at some of these chromosomes affected traits differently in animals with the form of myostatin that increases meat yield, compared to animals without this form of the gene. Locations of genes reported here need to be evaluated in other populations.
Technical Abstract: The effects of the bovine myostatin gene and additional quantitative trait loci (QTL) have been previously assessed. The objective of this study was to identify further QTL for economically important traits. Two half-sib families were developed from a Belgian Blue x MARC III (n = 246) and a Piedmontese x Angus (n = 209) sire. Traits analyzed were birth, weaning, and yearling weight (kg), preweaning average daily gain (kg/d), postweanin average daily gain (kg/d), hot carcass weight (kg), fat depth (cm), marbling score, longissimus muscle area (cm2), estimated kidney, pelvic, and heart fat (%), USDA yield grade, retail product yield (%), fat yield (%), and wholesale rib-fat yield (%). Meat tenderness was measured as Warner-Bratzler shear force at 3 and 14 d postmortem. A total of 89 markers were used. In the family with Belgian Blue inheritance, significant QTL (expected number of false positives = .025; ENFP) was identified for marbling score on chromosome 3. Suggestive QTL (ENFP = .5) were identified for retail product yield on chromosome 3, for hot carcass weight and postweaning average daily gain on chromosome 4, for fat depth and marbling score on chromosome 8, for 14-d Warner-Bratzler shear force on chromosome 9, and for marbling score on chromosome 10. Evidence suggesting the presence of an interaction for 3-d Warner-Bratzler shear force between myostatin and a QTL on chromosome 4 was detected. In the family of Piedmontese and Angus inheritance, evidence indicates the presence of an interaction for fat depth between myostatin and chromosome 8. Regions identified underlying quantitative trait loci need to be assessed in other populations.