Genes with major effects on wool traits detected in Finn cross sheep

Two Finn sires with short wool staple lengths (Finn-S1 91 mm, Finn-S2 107 mm) and two with long staple lengths (Finn-L1 147 mm, Finn-L2 133 mm) were joined with Dorset Down (staple length 37-120 mm) and Romney (staple length 105-166 mm) ewes. Over two years, each ram sired between 83 and 210 progeny. Wool characteristics of progeny were measured at 6 months of age. For all sire groups, distributions of fibre diameter, fibre curvature, fibre medullation and clean fleece weight were not significantly different from single normal distributions. Similarly the distributions of fibre diameter coefficient of variation (FDCV), staple-crimp frequency and staple length for progeny of Finn-S1, Finn-S2 and Finn-L1 were close to unimodal. In contrast, the same three traits for progeny of Finn-L2 fitted two normal distributions. For all three traits, the mean value of one of the distributions of Finn-L2 progeny was similar to the means of the other three sire groups, while the mean of the second distribution was 41% greater (FDCV), 65% greater (staple length) or 67% less (crimp frequency) than that of the first. These results suggest the presence of a gene or genes with major effects on fibre traits.