HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sorensen, D. A. Articles by Kennedy, B. W. Search for Related Content PubMed Articles by Sorensen, D. A. Articles by Kennedy, B. W.

Estimation of Response to Selection Using Least-Squares and Mixed Model Methodology^1,2,

University of Guelph³, Guelph, Ontario, Canada, N1G 2W1

Abstract

Properties of least-squares and mixed model estimators of response to selection are discussed. The least-squares estimator is unbiased provided that the records have been properly adjusted for fixed effects (for example, using a control line), that selection is within generations and that there is only one record/candidate for selection. In the case of the mixed model estimator, it is unbiased and individual breeding values have minimum variance of prediction error provided that selection is within levels of fixed effects and the variances of the random effects before selection are known. If certain conditions are met, the mixed model approach does not require the use of a control line in order to partition adequately phenotypic trend into its genetic and environmental components. Henderson's results are extended to a model that includes several cycles of selection. It is shown that the relationship matrix accounts for the decline in variance due to genetic drift and it circumvents further reduction in variance due to gametic disequilibrium. Results are illustrated with Monte Carlo simultation.

¹ Very useful discussions with R. Thompson, C. R. Henderson, R. L. Quaas and E. J. Poliak are gratefully acknowledged.

² Financial support was provided by the Natural Sciences and Engineering Research Council of Canada, the Holstein-Friesian Assoc. of Canada and the Ontario Ministry of Agriculture and Food.

³ Dept. of Anim. and Poul. Sci.

This article has been cited by other articles:

				M. E. Z. Mercadante, I. U. Packer, A. G. Razook, J. N. S. G. Cyrillo, and L. A. Figueiredo Direct and correlated responses to selection for yearling weight onreproductive performance of Nelore cows J Anim Sci, February 1, 2003; 81(2): 376 - 384. [Abstract] [Full Text] [PDF]

				A. Blasco, D. Sorensen, and J. P. Bidanel Bayesian Inference of Genetic Parameters and Selection Response for Litter Size Components in Pigs Genetics, May 1, 1998; 149(1): 301 - 306. [Abstract] [Full Text] [PDF]