Finding Major Gene Effects in Australian Meat Sheep - Feasibility Study for a Texel Dataset

Segregation analysis indicated the presence of major genes for three post-weaning traits; weight, eyemuscle depth and C fat, within a Texel based dataset obtained from LAMBPLAN. The effect of expressing one paternal copy (in phenotypic standard deviation units in brackets) was 2.71 kg (0.48) for weight, 1.05mm (0.50) for eye-muscle depth and -0.42mm (0.60) for C fat. Power calculations were used to determine the family sizes required to detect markers linked to these genes for both the halfsib (HS2) and grandprogeny (HS3) designs. Marker detection using the HS2 design required phenotypes on approximately 150 half-sibs, a feasable number within this breed.