tailieunhanh - Báo cáo sinh học: "Considerations on measures of precision and connectedness in mixed linear models of genetic evaluation"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Considerations on measures of precision and connectedness in mixed linear models of genetic evaluation | Genet Sei Evol 1996 28 359-378 Elsevier INRA 359 Original article Considerations on measures of precision and connectedness in mixed linear models of genetic evaluation D Laloe F Phocas F Ménissier Station de génétique quantitative et appliquée Institut national de la recherche agronomique 78352 Jouy-en-Josas cedex France Received 5 April 1995 accepted 24 May 1996 Summary - Three criteria for the quality of a genetic evaluation are compared the prediction error variance PEV the loss of precision due to the estimation of the fixed effects degree of connectedness IC and a criterion related to the information brought by the evaluation in terms of generalized coefficient and determination CD precision . These criteria are introduced through simple examples based on an animal model. The main differences between them are the choice of the matrix studied CD vs PEV IC the method used to account for the relationships CD vs PEV the use of a reference matrix or model PEV vs CD IC and the data design IC vs PEV CD . IC is shown to favor designs with limited information provided by the data and another index is suggested which minimizes this drawback. The behavior of IC and CD is studied in a hypothetical herd sire model. The precision criteria set a balance between connectedness level and information provided by the data whereas the connectedness criteria favor the model with minimum information and maximum connectedness level. Genetic relationships between animals decrease both PEV and genetic variability. PEV considers only the favorable effects on PEV CD accounts for both effects. CD sets a balance between the design and the information brought by the data the PEV and the genetic variability and is thus a method of choice for studying the quality of a genetic evaluation. genetic evaluation precision mixed linear model disconnectedness genetic progress Resume Quelques considerations à propos des mesures de precision et de connexion dans les modèles linéaires mixtes d .