tailieunhanh - Báo cáo sinh học: " Measuring connectedness among herds in mixed linear models: From theory to practice in large-sized genetic evaluations"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Measuring connectedness among herds in mixed linear models: From theory to practice in large-sized genetic evaluations | Genet. Sel. Evol. 40 2008 145-159 INRA EDP Sciences 2008 DOI gse 2007041 Available online at Original article Measuring connectedness among herds in mixed linear models From theory to practice in large-sized genetic evaluations Marie-Noelle FOUILLOUX1 Virginie ClEMENT2 Denis LALOE3 1 Institut de l Elevage Station de génétique quantitative et appliquée INRA 78352 Jouy-en-Josas France 2 Institut de l Elevage Station d amélioration génétique des animaux INRA 31326 Castanet-Tolosan France 3 Station de génétique quantitative et appliquée UR337 INRA 78352 Jouy-en-Josas France Received 8 February 2007 accepted 16 October 2007 Abstract - A procedure to measure connectedness among groups in large-sized genetic evaluations is presented. It consists of two steps a computing coefficients of determination CD of comparisons among groups of animals and b building sets of connected groups. The CD of comparisons were estimated using a sampling-based method that estimates empirical variances of true and predicted breeding values from a simulated n-sample. A clustering method that may handle a large number of comparisons and build compact clusters of connected groups was developed. An aggregation criterion Caco that reflects the level of connectedness of each herd was computed. This procedure was validated using a small beef data set. It was applied to the French genetic evaluation of the beef breed with most records and to the genetic evaluation of goats. Caco was more related to the type of service of sires used in the herds than to herd size. It was very sensitive to the percentage of missing sires. Disconnected herds were reliably identified by low values of Caco. In France this procedure is the reference method for evaluating connectedness among the herds involved in on-farm genetic evaluation of beef cattle IBOVAL since 2002 and for genetic evaluation of goats from 2007 onwards. connectedness clustering BLUP accuracy 1. INTRODUCTION The problem of .