TAILIEUCHUNG - Báo cáo sinh học: "Heterogeneity of variance for type traits in the Montbeliarde cattle breed"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh Original cung cấp cho các bạn kiến thức về sinh học đề tài: Heterogeneity of variance for type traits in the Montbeliarde cattle breed. | 545 Genet Sei Evol 1997 29 545-570 Elsevier Inra Original article Heterogeneity of variance for type traits in the Montbeliarde cattle breed c Robert-Granié V Ducrocq JL Foulley Station de génétique quantitative et appliquée Institut national de la recherche agronomique Centre de recherches de Jouy-en-Josas 78352 Jouy-en-Josas cedex France Received 3 April 1997 accepted 22 September 1997 Summary - This paper presents and discusses the estimation of genetic and residual co- variance components for conformation traits recorded in different environments using mixed linear models. Testing procedures for genetic parameters genetic correlations between environments constant or equal to one genetic correlation equal to one and constant intra-class correlations homogeneity of variance-covariance components are presented. These hypotheses were described via heteroskedastic univariate sire models taking into account genotype X environment interaction. An expectation-maximization EM algorithm was proposed for calculating restricted maximum likelihood REML estimates of the residual and genetic components of variances and co-variances. Likelihood ratio tests were suggested to assess hypotheses concerning genetic parameters. The procedures presented in the paper were used to analyze and to detect sources of variation on conformation traits in the Montbeliarde cattle breed using 24 301 progeny records of 528 sires. On all variables analyzed several sources stage of lactation classifiers type of housing of heterogeneity of residual and genetic variances were clearly highlighted but intra-class correlations between environments of type traits remained generally constant. heteroskedasticity mixed model genotype X environment interaction I EM algorithm REML estimation Resume Hétérogénéité des variances de caractère d animaux de race Montbéliarde. Get article présente et discute I estimation des composantes de co variance génétiques et résiduelles de caractères de conformation mesurés

• Báo cáo khoa học
• Báo cáo sinh học hay
• cách trình bày báo cáo
• báo cáo sinh học
• công trình nghiên cứu sinh học
• tài liệu về sinh học