title: Genome-wide association and genomic prediction of breeding values for fatty acid composition in subcutaneous adipose and longissimus lumborum muscle of beef cattle.
abstract: BACKGROUND
  Identification of genetic variants that are associated with fatty acid composition in beef will enhance our understanding of host genetic influence on the trait and also allow for more effective improvement of beef fatty acid profiles through genomic selection and marker-assisted diet management. In this study, 81 and 83 fatty acid traits were measured in subcutaneous adipose (SQ) and longissimus lumborum muscle (LL), respectively, from 1366 purebred and crossbred beef steers and heifers that were genotyped on the Illumina BovineSNP50 Beadchip. The objective was to conduct genome-wide association studies (GWAS) for the fatty acid traits and to evaluate the accuracy of genomic prediction for fatty acid composition using genomic best linear unbiased prediction (GBLUP) and Bayesian methods.
  
  
  RESULTS
  In total, 302 and 360 significant SNPs spanning all autosomal chromosomes were identified to be associated with fatty acid composition in SQ and LL tissues, respectively. Proportions of total genetic variance explained by individual significant SNPs ranged from 0.03 to 11.06% in SQ, and from 0.005 to 24.28% in the LL muscle. Markers with relatively large effects were located near fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD), and thyroid hormone responsive (THRSP) genes. For the majority of the fatty acid traits studied, the accuracy of genomic prediction was relatively low (<0.40). Relatively high accuracies (> = 0.50) were achieved for 10:0, 12:0, 14:0, 15:0, 16:0, 9c-14:1, 12c-16:1, 13c-18:1, and health index (HI) in LL, and for 12:0, 14:0, 15:0, 10 t,12c-18:2, and 11 t,13c + 11c,13 t-18:2 in SQ. The Bayesian method performed similarly as GBLUP for most of the traits but substantially better for traits that were affected by SNPs of large effects as identified by GWAS.
  
  
  CONCLUSIONS
  Fatty acid composition in beef is influenced by a few host genes with major effects and many genes of smaller effects. With the current training population size and marker density, genomic prediction has the potential to predict the breeding values of fatty acid composition in beef cattle at a moderate to relatively high accuracy for fatty acids that have moderate to high heritability.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. liuhong@ualberta.ca.|Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. liuhong@ualberta.ca.
authors.forename: Liuhong
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. ekine@ualberta.ca.
authors.forename: Chinyere
authors.initials: C
authors.lastname: Ekine-Dzivenu
authors.affiliation: Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. michael.vinsky@ualberta.ca.
authors.forename: Michael
authors.initials: M
authors.lastname: Vinsky
authors.affiliation: Lacombe Research Centre, Alberta Agriculture and Forestry, 6000 C & E Trail, Lacombe, AB, T4L 1 W1, Canada. John.Basarab@gov.ab.ca.
authors.forename: John
authors.initials: J
authors.lastname: Basarab
authors.affiliation: Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. jennifer.aalhus@agr.gc.ca.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Aalhus
authors.affiliation: Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. mike.dugan@agr.gc.ca.
authors.forename: Mike E R
authors.initials: ME
authors.lastname: Dugan
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. carolyn.fitzsimmons@agr.gc.ca.|Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. carolyn.fitzsimmons@agr.gc.ca.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Fitzsimmons
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. stothard@ualberta.ca.
authors.forename: Paul
authors.initials: P
authors.lastname: Stothard
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. changxi.li@arg.gc.ca.|Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, T4L 1 W1, Canada. changxi.li@arg.gc.ca.
authors.forename: Changxi
authors.initials: C
authors.lastname: Li
mesh_terms: D000818:Animals; D064131:Back Muscles / Q000737:chemistry*; D002417:Cattle / Q000235:genetics*; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D055106:Genome-Wide Association Study; D008297:Male; D020641:Polymorphism, Single Nucleotide; D000069466:Red Meat / Q000032:analysis*
chemical_list: D005227:Fatty Acids