TAILIEUCHUNG - Báo cáo sinh học: "Selection for uniformity in livestock by exploiting genetic heterogeneity of residual variance"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Selection for uniformity in livestock by exploiting genetic heterogeneity of residual variance | Genet. Sel. Evol. 40 2008 37-59 Available online at INRA EDP Sciences 2008 DOI gse 2007034 Original article Selection for uniformity in livestock by exploiting genetic heterogeneity of residual variance Han A. MULDER1 Piter BIJMA1 William G. HILL2 1 Animal Breeding and Genomics Centre Wageningen University 6700 AH Wageningen The Netherlands 2 Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh EH9 3JT UK Received 30 January 2007 accepted 23 August 2007 Abstract - In some situations it is worthwhile to change not only the mean but also the variability of traits by selection. Genetic variation in residual variance may be utilised to improve uniformity in livestock populations by selection. The objective was to investigate the effects of genetic parameters breeding goal number of progeny per sire and breeding scheme on selection responses in mean and variance when applying index selection. Genetic parameters were obtained from the literature. Economic values for the mean and variance were derived for some standard non-linear profit equations . for traits with an intermediate optimum. The economic value of variance was in most situations negative indicating that selection for reduced variance increases profit. Predicted responses in residual variance after one generation of selection were large in some cases when the number of progeny per sire was at least 50 by more than 10 of the current residual variance. Progeny testing schemes were more efficient than sib-testing schemes in decreasing residual variance. With optimum traits selection pressure shifts gradually from the mean to the variance when approaching the optimum. Genetic improvement of uniformity is particularly interesting for traits where the current population mean is near an intermediate optimum. heterogeneity of variance index selection uniformity economic value optimum trait 1. INTRODUCTION Uniformity of livestock is of economic

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