TAILIEUCHUNG - Báo cáo sinh học: " Inferences about variance components and selection response for body weight in chickens"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Inferences about variance components and selection response for body weight in chickens | Genet Sei Evol 1997 29 413-425 Elsevier Inra 413 Original article Inferences about variance components and selection response for body weight in chickens G Su p S0rensen D Sorensen Department of Breeding and Genetics Danish Institute of Animal Science PO Box 39 8830 Tjele Denmark Received 6 January 1997 accepted 13 June 1997 Summary - Response to selection for body weight at 40 days was analyzed using least squares a REML BLUP approach and finally using Bayesian methods. The last two methods were implemented using an animal model that included a term accounting for a covariance among full-sibs effect other than the additive genetic. The data which originate from the Strynp breeding station in Denmark comprised 6 900 recorded individuals from 200 sires and 720 dams and covered eight generations of selection. The base population was formed from a population with a long history of selection for body weight. The least squares procedure yielded a total phenotypic change of g. The estimate of total genetic change based on REML BLUP was g and the Bayesian approach produced an estimate mean of the marginal posterior distribution ranging from to g depending on the prior distribution assumed for the variance components. This corresponds to a response per generation of about 45 g or of the mean of the base population. The Bayesian approach was implemented using the Gibbs sampler. The REML estimates of heritability and of the proportion of the variance due to the f effect were and respectively. The corresponding values obtained from the Bayesian analysis were approximately and regardless of the prior used. A likelihood ratio test indicated that the variance component due to the f effect should be included in the model. We speculate about the possible mechanisms that can lead to the f effect. selection daily gain in broilers Bayesian analysis Gibbs sampling Resume - Inferences concernant les composantes de la variance et la .

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