Mapping of multiple quantitative trait loci for growth and carcass traits in a complex commercial sheep pedigree

AF McRae*, SC Bishop, GA Walling, AD Wilson, PM Visscher

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The confirmation of the segregation of experimentally discovered quantitative trait loci (QTL) in a variety of commercial populations is required before their commercial significance can be fully realized. The use of complex pedigrees in the design of such confirmation experiments has the potential to increase the probability of the QTL segregating within the pedigree while maintaining the power to detect this segregation. Here a QTL analysis is applied across candidate chromosomes of a complex pedigree of 570 Charollais sheep from commercial flocks in the UK. This pedigree also contained a moderately sized half-sib family which was analysed separately. Two QTL significant at the 5% chromosome-wide level were detected in the half-sib analysis and seven were detected in a maximum likelihood variance component analysis of the complex pedigree using identity-by-descent values estimated by Markov chain Monte Carlo methods. The estimation of OTL effects was achieved by fitting all QTL for a specific trait simultaneously, reducing the large upward bias observed in the single QTL models. Both methods of analysis detected QTL for live weight, although these mapped to different regions, and the variance components method detected QTL for ultrasonically measured fat depth. This analysis demonstrates the viability of applying a variance component analysis to large pedigrees with the presence of considerable inbreeding.

Original languageEnglish
Pages (from-to)135-141
Number of pages7
JournalAnimal science
Publication statusPublished - Apr 2005

Keywords / Materials (for Non-textual outputs)

  • carcass composition
  • Charollais
  • fat thickness
  • QTL
  • variance components


Dive into the research topics of 'Mapping of multiple quantitative trait loci for growth and carcass traits in a complex commercial sheep pedigree'. Together they form a unique fingerprint.

Cite this