Genet. Sel. Evol. 34 (2002) 705-728
DOI: 10.1051/gse:2002026

Detection of quantitative trait loci for carcass composition traits in pigs

Denis Milan^a, Jean-Pierre Bidanel^b, Nathalie Iannuccelli^a, Juliette Riquet^a, Yves Amigues^c, Joseph Gruand^d, Pascale Le Roy^b, Christine Renard^e and Claude Chevalet<sup>a

a</sup>  Laboratoire de génétique cellulaire, Institut national de la recherche agronomique, 31326 Castanet-Tolosan Cedex, France
^b  Station de génétique quantitative et appliquée, Institut national de la recherche agronomique, 78352 Jouy-en-Josas Cedex, France
^c  LABOGENA, Institut national de la recherche agronomique, 78352 Jouy-en-Josas Cedex, France
^d  Station expérimentale de sélection porcine, Institut national de la recherche agronomique, 86480 Rouillé, France
^e  Laboratoire de radiobiologie et d'étude du génome, Institut national de la recherche agronomique, 78352 Jouy-en-Josas Cedex, France

(Received 9 January 2002; accepted 9 April 2002)

Abstract
A quantitative trait locus (QTL) analysis of carcass composition data from a three-generation experimental cross between Meishan (MS) and Large White (LW) pig breeds is presented. A total of 488 F2 males issued from six F1 boars and 23 F1 sows, the progeny of six LW boars and six MS sows, were slaughtered at approximately 80 kg live weight and were submitted to a standardised cutting of the carcass. Fifteen traits, i.e. dressing percentage, loin, ham, shoulder, belly, backfat, leaf fat, feet and head weights, two backfat thickness and one muscle depth measurements, ham + loin and back + leaf fat percentages and estimated carcass lean content were analysed. Animals were typed for a total of 137 markers covering the entire porcine genome. Analyses were performed using a line-cross (LC) regression method where founder lines were assumed to be fixed for different QTL alleles and a half/full sib (HFS) maximum likelihood method where allele substitution effects were estimated within each half-/full-sib family. Additional analyses were performed to search for multiple linked QTL and imprinting effects. Significant gene effects were evidenced for both leanness and fatness traits in the telomeric regions of SSC 1q and SSC 2p, on SSC 4, SSC 7 and SSC X. Additional significant QTL were identified for ham weight on SSC 5, for head weight on SSC 1 and SSC 7, for feet weight on SSC 7 and for dressing percentage on SSC X. LW alleles were associated with a higher lean content and a lower fat content of the carcass, except for the fatness trait on SSC 7. Suggestive evidence of linked QTL on SSC 7 and of imprinting effects on SSC 6, SSC 7, SSC 9 and SSC 17 were also obtained.

Key words: pig / gene mapping / quantitative trait locus / carcass composition

Correspondence and reprints: Denis Milan,
    e-mail: milan@toulouse.inra.fr; Jean-Pierre Bidanel,
    e-mail: bidanel@dga.jouy.inra.fr

© INRA, EDP Sciences 2002