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Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance | Genet. Sel. Evol. 36 2004 297-324 INRA EDP Sciences 2004 DOI 10.1051 gse 2004003 297 Original article Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance Jack C.M. Dekkers Reena Chakraborty Department of Animal Science 225C Kildee Hall Iowa State University Ames IA 50011 USA Received 9 April 2003 accepted 17 December 2003 Abstract - A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects but substantial for QTL with over-dominance for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For overdominant QTL maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing. crossbreeding selection quantitative trait loci marker assisted selection 1. INTRODUCTION In most livestock production systems crossbreds are used for commercial production to capitalize on heterosis and complementarity and the aim of selection within pure-lines is to maximize crossbred performance. Selection is however within pure-lines and primarily based on purebred data which may not maximize genetic progress in crossbred performance 21 . Several theoretical .
