TAILIEUCHUNG - Báo cáo sinh học: "Approximate restricted maximum likelihood and approximate prediction"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Approximate restricted maximum likelihood and approximate prediction | 331 Genet Sei Evol 1992 24 331-343 Elsevier INRA Original article Approximate restricted maximum likelihood and approximate prediction error variance of the Mendelian sampling effect D Boichard1 LR Schaeffer2 A J Lee3 1 Institut National de la Recherche Agronomique Station de Génétique Quantitative et Appliquée 78352 Jouy-en-Josas Cedex France 2 Centre for Genetic Improvement of Livestock University of Guelph Ontario NIG 2W1 3 Agriculture Canada Animal Research Centre Ottawa Ontario KIA 0C6 Canada Received 26 August 1991 accepted 14 May 1992 Summary - In an Expectation-Maximization type Restricted Maximum Likelihood REML procedure the estimation of a genetic co- variance component involves the trace of the product of the inverse of the coefficient matrix by the inverse of the relationship matrix. Computation of this trace is usually the limiting factor of this procedure. In this paper a method is presented to approximate this trace in the case of an animal model by using an equivalent model based on the Mendelian sampling effect and by simplifying its coefficient matrix and its inversion. This approximation appeared very accurate for low heritabilities but was downwards biased when the heritability was high. Implemented in a REML procedure this approximation reduced dramatically the amount of computation but provided downwards biased estimates of genetic variances. Several examples are presented to illustrate the method. variance and covariance components restricted maximum likelihood Mendelian sampling effect animal model Resume Approximation du maximum de vraisemblance restreinte et de la variance d erreur de prediction de 1 aléa de méiose. Dans certaines procedures de Maximum de Vraisemblance Restreint REML I estimation des composantes de co variance génétique implique le calcul de la trace du produit de I inverse de la matrice des coefficients par I inverse de la matrice de parentés calcul qui constitue généralement le facteur limitant de ce type de procedure.

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