Submitted to: Genetics and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2003
Publication Date: 9/29/2003
Citation: MACHADO, M.B., ALENCAR, M.M., PEREIRA, A.P., OLIVERIA, H.N., CASAS, E., COUTINHO, L.L., REGITANO, L.C. QTL AFFECTING BODY WEIGHT IN A CANDIDATE REGION OF CATTLE CHROMOSOME 5. GENETICS AND MOLECULAR BIOLOGY. 2003. v. 26(3) p. 259-265. Interpretive Summary: Weights at different ages are good selection criteria for selection for growth in beef cattle. Birth, weaning and yearling weights are representative weights for growth. The region on the genetic material where genes that control economically important traits reside is called a quantitative trait loci (QTL). To date, there have been several studies in which the QTL for birth, weaning and yearling weights have been detected on bovine chromosome 5, however, this is the first report of a QTL for birth and yearling weight in a synthetic breed developed in Brazil. The results of this study confirm previous reports of a QTL for birth weight on this chromosome. Selection of genes that could potentially be responsible for the effect of the QTL has been done and further studies will be needed to establish the effects of these genes.
Technical Abstract: The objective of this work was to identify QTLs for liveweights in a candidate region of bovine chromosome 5. Half-sib families from two lines, one traditional and the other new, of Canchim beef cattle breed (5/8 Charolais + 3/8 Zebu) were genotyped for four microsatellite markers, including the microsatellite in the IGF-1 promoter region. Significant differences in allele distribution between the two lines were found with three markers. Results from interval mapping analyses indicated the presence of QTL (P < 0.05) within this region controlling birth weight and of a QTL influencing breeding value for yearling weight (P < 0.01) in the new line of breed. Interaction between IGF-1 genotype and genetic group found previously reinforces the hypothesis of a linked QTL instead of IGF-1 (insulin-like growth factor-1) effect on growth traits.