Theoretical and Applied Genetics

, Volume 93, Issue 1–2, pp 71–80

Methods for multiple-marker mapping of quantitative trait loci in half-sib populations

  • S. A. Knott
  • J. M. Elsen
  • C. S. Haley

DOI: 10.1007/BF00225729

Cite this article as:
Knott, S.A., Elsen, J.M. & Haley, C.S. Theoret. Appl. Genetics (1996) 93: 71. doi:10.1007/BF00225729


In this paper we consider the detection of individual loci controlling quantitative traits of interest (quantitative trait loci or QTLs) in the large half-sib family structure found in some species. Two simple approaches using multiple markers are proposed, one using least squares and the other maximum likelihood. These methods are intended to provide a relatively fast screening of the entire genome to pinpoint regions of interest for further investigation. They are compared with a more traditional single-marker least-squares approach. The use of multiple markers is shown to increase power and has the advantage of providing an estimate for the location of the QTL. The maximum-likelihood and the least-squares approaches using multiple markers give similar power and estimates for the QTL location, although the likelihood approach also provides estimates of the QTL effect and sire heterozygote frequency. A number of assumptions have been made in order to make the likelihood calculations feasible, however, and computationally it is still more demanding than the least-squares approach. The least-squares approach using multiple markers provides a fast method that can easily be extended to include additional effects.

Key words

QTL mapping Genetic mapping Animal breeding Half-sibs 

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • S. A. Knott
    • 3
  • J. M. Elsen
    • 4
  • C. S. Haley
    • 3
  1. 1.Institute of Cell, Animal and Population Biology, University of EdinburghEdinburghUK
  2. 2.Roslin InstituteEdinburghUK
  3. 3.INRA Station de Génétique Quantitative et AppliquéeJouy-en-JosasFrance
  4. 4.INRA Station d'Amélioration Génétique des AnimauxCastanet-TolosanFrance

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