tailieunhanh - Báo cáo sinh học: " Changes in genetic correlations by index selection Y Itoh"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Changes in genetic correlations by index selection Y Itoh | Genet Sei Evol 1991 23 301-308 Elsevier INRA 301 Original article Changes in genetic correlations by index selection Y Itoh Kyoto University Department of Animal Science Faculty of Agriculture Kyoto 606 Japan Received 13 August 1990 accepted 5 June 1991 Summary - A formula expressing changes in genetic variances and covariances by index selection in one generation is derived. Then changes in genetic correlation are discussed in 2 simple cases using that formula. When 2 traits involved in the index have equal heritabilities and equal weights the change in the genetic correlation is always negative and generally large. When selection is on one trait the genetic correlation with another trait after selection is inclined toward zero. selection index genetic correlation Bulmer effect Resume Changements des correlations génétiques dũs à la selection sur indice. Une formule est établie pour exprimer les changements des variances et covariances génétiques dũs à la selection sur indice. Les changements des correlations génétiques sont ensuite discutés dans 2 situations simples à I aide de cette formule. Quand les 2 caractères de I indice ont des héritabilités el des coefficients de pondération égaux le changement de la correlation génétique est toujours negatif et généralement important. Quand la selection se fait sur un caractère les correlations génétiques avec les autres caractères tendent à se rapprocher de zero. indice de selection correlation génétique effet Bulmer INTRODUCTION Assuming a trait influenced by many loci Bulmer 1971 showed that a substantial change in additive genetic variance due to selection is caused by gamete phase disequilibrium and derived a formula for the disequilibrium component of the genetic variance. Tallis 1987 proposed an alternative procedure which obtained the same result as that of Bulmer 1971 and extended it to be applicable to multiple traits. Furthermore Tallis and Leppard 1988 studied the joint effects of index selection and .

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