tailieunhanh - Báo cáo khoa hoc:" Bayes factors for detection of Quantitative Trait Loci"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Bayes factors for detection of Quantitative Trait Loci | Genet Sei. Evol. 33 2001 133-152 INRA EDP Sciences 2001 133 Original article Bayes factors for detection of Quantitative Trait Loci Luis Varonaa Luis Alberto García-Cortésb Miguel Pérez-Encisoa a Area de Producció Animal Centre UdL-IRTA c Rovira Roure 177 25198 Lleida Spain b Unidad de Genética Cuantitativa Y Mejora Animal Universidad de Zaragoza 50013 Zaragoza Spain Received 8 November 1999 accepted 24 October 2000 Abstract - a fundamental issue in quantitative trait locus QTL mapping is to determine the plausibility of the presence of a QTL at a given genome location. Bayesian analysis offers an attractive way of testing alternative models here QTL Vi. no-QTL via the Bayes factor. There have been several numerical approaches to computing the Bayes factor mostly based on Markov Chain Monte Carlo MCMC but these strategies are subject to numerical or stability problems. We propose a simple and stable approach to calculating the Bayes factor between nested models. The procedure is based on a reparameterization of a variance component model in terms of intra-class correlation. The Bayes factor can then be easily calculated from the output of a MCMC scheme by averaging conditional densities at the null intra-class correlation. We studied the performance of the method using simulation. We applied this approach to QTL analysis in an outbred population. We also compared it with the Likelihood Ratio Test and we analyzed its stability. Simulation results were very similar to the simulated parameters. The posterior probability of the QTL model increases as the QTL effect does. The location of the QTL was also correctly obtained. The use of meta-analysis is suggested from the properties of the Bayes factor. Bayes factor Quantitative Trait Loci hypothesis testing Markov Chain Monte Carlo 1. introduction Mapping of quantitative trait loci QTLs is a rapidly evolving topic in Statistical Genomics. Several procedures have been described for mapping QTLs in experimental crosses 10

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