title: Impact of two myostatin (MSTN) mutations on weight gain and lamb carcass classification in Norwegian White Sheep (Ovis aries).
abstract: BACKGROUND
  Our aim was to estimate the effect of two myostatin (MSTN) mutations in Norwegian White Sheep, one of which is close to fixation in the Texel breed.
  
  
  METHODS
  The impact of two known MSTN mutations was examined in a field experiment with Norwegian White Sheep. The joint effect of the two MSTN mutations on live weight gain and weaning weight was studied on 644 lambs. Carcass weight gain from birth to slaughter, carcass weight, carcass conformation and carcass fat classes were calculated in a subset of 508 lambs. All analyses were carried out with a univariate linear animal model.
  
  
  RESULTS
  The most significant impact of both mutations was on conformation and fat classes. The largest difference between the genotype groups was between the wild type for both mutations and the homozygotes for the c.960delG mutation. Compared to the wild types, these mutants obtained a conformation score 5.1 classes higher and a fat score 3.0 classes lower, both on a 15-point scale.
  
  
  CONCLUSIONS
  Both mutations reduced fatness and increased muscle mass, although the effect of the frameshift mutation (c.960delG) was more important as compared to the 3'-UTR mutation (c.2360G>A). Lambs homozygous for the c.960delG mutation grew more slowly than those with other MSTN genotypes, but had the least fat and the largest muscle mass. Only c.960delG showed dominance effects.
authors.affiliation: Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences (UMB), PO Box 5003, N-1432 As, Norway. iab@nsg.no
authors.forename: Inger A
authors.initials: IA
authors.lastname: Boman
authors.forename: Gunnar
authors.initials: G
authors.lastname: Klemetsdal
authors.forename: Ola
authors.initials: O
authors.lastname: Nafstad
authors.forename: Thor
authors.initials: T
authors.lastname: Blichfeldt
authors.forename: Dag I
authors.initials: DI
authors.lastname: Våge
mesh_terms: D000818:Animals; D005838:Genotype; D009154:Mutation; D055435:Myostatin / Q000235:genetics*; D009664:Norway; D034561:Sheep, Domestic / Q000235:genetics*; D015430:Weight Gain
chemical_list: D055435:Myostatin