Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Bayesian estimation of dispersion parameters with a reduced animal model including polygenic and QTL effects | 103 Genet. Sei. Evol. 30 1998 103-125 Inra Elsevier Paris Original article Bayesian estimation of dispersion parameters with a reduced animal model including polygenic and QTL effects Marco . Binka Richard L. Quaasb Johan . Van Arendonka a Animal Breeding and Genetics Group Wageningen Institute of Animal Sciences Wageningen Agricultural University PO Box 338 6700 AH Wageningen the Netherlands b Department of Animal Science Cornell University Ithaca NY 14853 USA Received 21 April 1997 accepted 29 December 1997 Abstract - In animal breeding Markov chain Monte Carlo algorithms are increasingly used to draw statistical inferences about marginal posterior distributions of parameters in genetic models. The Gibbs sampling algorithm is most commonly used and requires full conditional densities to be of a standard form. In this study we describe a Bayesian method for the statistical mapping of quantitative trait loci QTL where the application of a reduced animal model leads to non-standard densities for dispersion parameters. The Metropolis Hastings algorithm is used to obtain samples from these non-standard densities. The flexibility of the Metropolis Hastings algorithm also allows US change the parameterization of the genetic model. Alternatively to the usual variance components we use one variance component residual and two ratios of variance components . heritability and proportion of genetic variance due to the QTL to parameterize the genetic model. Prior knowledge on ratios can more easily be implemented partly by absence of scale effects. Three sets of simulated data are used to study performance of the reduced animal model parameterization of the genetic model and testing the presence of the QTL at a fixed position. Inra Elsevier Paris reduced animal model dispersion parameters Markov chain Monte Carlo quantitative trait loci Resume - Estimation Bayésienne des paramètres de dispersion dans un modèle animal réduit comprenant un effet polygénique et 1 effet
