Genetic variation in the ovine uncoupling protein 1 gene: association with carcass traits in New Zealand (NZ) Romney sheep, but no association with growth traits in either NZ Romney or NZ Suffolk sheep.

The uncoupling protein 1 (UCP1) plays an important role in the regulation of lipolysis and thermogenesis in adipose tissues. Genetic variation within three regions (the promoter, intron 2 and exon 5) of the ovine UCP1 gene (UCP1) was investigated using polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analyses. These revealed three promoter variants (designated A, B and C) and two intron 2 variants (a and b). The association of this genetic variation with variation in lamb carcass traits and postweaning growth was investigated in New Zealand (NZ) Romney and Suffolk sheep. The presence of B in a lamb's genotype was associated with decreased subcutaneous carcass fat depth (V-GR) (p = 0.004) and proportion of total lean meat yield of loin meat (p = 0.005), and an increased proportion of total lean meat yield of hind-leg meat (p = 0.018). In contrast, having two copies of C was associated with increased V-GR (p < 0.001) and proportion of total lean meat yield of shoulder meat (p = 0.009), and a decreased hind-leg yield (p = 0.032). No associations were found with postweaning growth. These results suggest that ovine UCP1 is a potential gene marker for carcass traits.