Effect of variation in ovine WFIKKN₂ on growth traits appears to be gender-dependent

WFIKKN₂ may play a role in the regulation of muscle growth and development, but to date there have been no reports on the effect of variation in WFIKKN₂ on growth and carcass traits in livestock. In this study, the effect of variation in ovine WFIKKN₂ was investigated in 800 New Zealand Romney lambs (395 male and 405 female), with five previously described variants (A to E) being identified. Variation in ovine WFIKKN₂ was not found to affect various growth traits in the female lambs, but the presence of variant B was associated (P < 0.05) with decreased birth weight, tailing weight, weaning weight and pre-weaning growth rate; and increased post-weaning growth rate in male lambs. In male lambs, the presence of variant B was associated (P < 0.05) with an increased shoulder yield and proportion shoulder yield. No associations with growth or carcass traits were detected for the presence (or absence) of the other variants. These results suggest that variation in ovine WFIKKN₂ may have a differential effect on growth in male and female lambs, and hence that the gene may be expressed in, or act in, a gender-specific fashion