Estimation of the proportion of genetic variation accounted for by DNA tests

An increasingly relevant question in evaluating commercial DNA tests is "What proportion of the additive genetic variation in the target trait is accounted for by the test? " Therefore, several estimators of this quantity were evaluated by simulation of a population of 1000 animals with 100 sires, each with 10 progeny. Three heritabilities (0.1, 0.3, and 0.5) of the target trait and four proportions of genetic variation (0.04, 0.16, 0.36, and 0.64) accounted for by the molecular breeding value (MBV) for the DNA test were simulated. The first estimator evaluated is the reduction in estimated sire variance (R̂gRV2) when the MBV is added as a fixed covariate to a single-trait model for the target trait divided by the sire variance from the model without the MBV. The second estimator is based on the regression of phenotype on MBV (R̂gRPM2) from a single trait sire model in which the MBV is a fixed covariate (this is the model that has been standard in independent validations since DNA tests began being reported as MBV). This estimator is computed as R̂gRPM 2 ≅ b