tailieunhanh - Báo cáo sinh học: " Multivariate restricted maximum likelihood estimation of genetic parameters for production traits in three selected turkey strains"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Multivariate restricted maximum likelihood estimation of genetic parameters for production traits in three selected turkey strains | Genet Sei Evol 1996 28 197-215 Elsevier INRA 197 Original article Multivariate restricted maximum likelihood estimation of genetic parameters for production traits in three selected turkey strains H Chapuis1 2 M Tixier-Boichard3 Y Delabrosse2 V Ducrocq1 1 Station de génétique quantitative et appliquée Institut national de la recherche agronomique domaine de Vilvert 78352 Jouy-en-Josas cedex 2 Betina Selection Le Beau Chêne Trédion 56250 Elven 3 Laboratoire de génétique factorielle Institut national de la recherche agronomique domaine de Vilvert 78352 Jouy-en-Josas cedex France Received 22 May 1995 accepted 5 December 1995 Summary - Genetic parameters related to growth carcass composition and egg production were estimated on three two female and one male commercial strains of turkey using the method of restricted maximum likelihood REML . In order to account for the sexual dimorphism in turkeys body weight BW measured at 12 and 16 weeks of age was considered as a sex-limited trait. As many as seven traits were analyzed simultaneously in one strain. Egg numbers were normalized using a Box-Cox transformation. Three different genetic models were used. The first one was a linear mixed model with a direct genetic effect. Model 2 accounted in addition for a dam s environmental effect while model 3 introduced a maternal genetic effect. The heritability estimates of BW were very high especially for female traits for female BW16 and for male BW16 in strain B . Sexual dimorphism was less heritable and for the 16 weeks body weight sex difference in the three strains considered . One of the female strains exhibited a strongly negative genetic correlation between female BW and egg number. The elevated values of the estimates probably originated from the method used which accounted for the bias due to the sequential selection that had been carried out and from the choice of the base population. Use of models 2 and 3 resulted in slightly lower .