title: Detection and modelling of time-dependent QTL in animal populations.
abstract: A longitudinal approach is proposed to map QTL affecting function-valued traits and to estimate their effect over time. The method is based on fitting mixed random regression models. The QTL allelic effects are modelled with random coefficient parametric curves and using a gametic relationship matrix. A simulation study was conducted in order to assess the ability of the approach to fit different patterns of QTL over time. It was found that this longitudinal approach was able to adequately fit the simulated variance functions and considerably improved the power of detection of time-varying QTL effects compared to the traditional univariate model. This was confirmed by an analysis of protein yield data in dairy cattle, where the model was able to detect QTL with high effect either at the beginning or the end of the lactation, that were not detected with a simple 305 day model.
authors.affiliation: Faculty of Agricultural Sciences, Department of Genetics and Biotechnology, University of Aarhus, Research Center Foulum, P.O. Box 50 8830 Tjele, Denmark. Mogens.Lund@agrsci.dk
authors.forename: Mogens S
authors.initials: MS
authors.lastname: Lund
authors.forename: Peter
authors.initials: P
authors.lastname: Sorensen
authors.forename: Per
authors.initials: P
authors.lastname: Madsen
authors.forename: Florence
authors.initials: F
authors.lastname: Jaffrézic
mesh_terms: D000483:Alleles; D000818:Animals; D002417:Cattle / Q000235:genetics*; D003198:Computer Simulation; D005260:Female; D007774:Lactation; D016013:Likelihood Functions; D011506:Proteins / Q000378:metabolism; D040641:Quantitative Trait Loci / Q000235:genetics*; D013997:Time Factors
chemical_list: D011506:Proteins