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Efficiency of estimation of variance and covariance components from full-sib group means for continuous or binary records

Gjøen, H.M., Simianer, H., Gjerde, B.
Journal of animal breeding and genetics 1997 v.114 no.1-6 pp. 349-362
covariance, digestive system, fecundity, fish, genetic correlation, genetic variance, heritability, models, phenotypic variation, variance
SUMMARY: High fecundity in fish allows for testing of large full-sib groups and testing of sub-samples of each group for different traits in different environments, and this benefit is especially useful when traits cannot be measured on the breeding candidate itself. A MIVQUE-method that compresses the information in such data, by estimating variance components based on full-sib mean data, is presented for a two-trait model. The efficiency of this method is compared in a simulation study with a model using an individual observation vector when estimating additive genetic and residual (co)variances. The effect on efficiency of continuous versus binary traits, of varied average number of full-sibs, of varied frequencies in the binary traits, of different combinations of frequencies in the two binary traits, of different heritabilities, of different genetic correlations, and of two different design sizes were studied. Generally, all parameters influenced the efficiency, and this influence was larger on the residual, than on the additive genetic variance component. The proposed methodology will be especially well-suited for analysing binary traits because the residual variance component can be calculated via the phenotypic variance, which can be estimated on basis of the frequency of the trait.