Genetic variances due to imprinted genes in cattle

Abstract

The effect of paternally expressed, i.e. maternally imprinted, genes on slaughter records from 2744 German Gelbvieh finishing bulls were estimated. Significant effects of paternal gametes were found for two fatness traits and an estimate of meat content. Paternally expressed genes explained 14 and 16% of the phenotypic variances for pelvic fat and kidney fat, respectively. Ignoring paternal gametic effects resulted in inflated estimates of the additive genetic variances. The heritabilities of pelvic and kidney fat dropped from 0.31 to 0.16 and from 0.59 to 0.28, respectively, when paternal gametes were fitted. A 15% influence of paternally expressed genes and a reduction in heritability of 20% were also found for estimated meat content. Simulation studies demonstrated that the uncorrelated random effect of the sire is a useful indicator for the presence of paternal gametic effects in variance component estimations. The presented results correspond well with findings in swine, where a paternally expressed 'QTL' at the 'Igf2' gene influences similar trait complexes. A viable speculation could therefore be that an imprinted bovine 'Igf2' gene caused the effects described here.