Detection of�quantitative trait loci for�carcass composition traits in pigs

Abstract

-A quantitative trait locus (QTL) analysis of carcass composition data from a threegeneration 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 * Correspondence and reprints E-mail: milan@toulouse.inra.fr, bidanel@dga.jouy.inra.fr 706 D. Milan et al. 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. pig / gene mapping / quantitative trait locus / carcass composition

Linked and pleiotropic QTLs influencing carcass composition traits detected on porcine chromosome 7

“…Phenotypic data were adjusted for systematic environmental effects (and slaughter weight for carcass cuts) as described in Milan et al (2002). Further details on the measures can be found in Bidanel et al (2001), Milan et al (2002) and .…”

“…To illustrate the technique, this strategy was applied in a Large WhiterMeishan pig cross to fatness and carcass composition traits in the SLA region where QTLs had already been described (Bidanel et al, 2001Milan et al, 2002). The four carcass fatness characteristics are routinely recorded and efficiently selected in French pig populations (see Tribout et al, 2004).…”

Polymorphism of the Porcine Leptin Gene Promoter and Analysis of Its Association with Gene Expression and Fatness Traits

“…With regard to fatness traits, five regions in porcine chromosomes 1, 2, 5, 7, and X were indicated (Milan et al, 2002). Chromosome 18, however, harboring the leptin gene (LEP), recognized as yet another candidate for fatness traits, was rarely shown to carry a QTL for these traits (Dragos-Wendrich et al, 2003;Malek et al, 2001).…”

Molecular characterization of the BTG2 and BTG3 genes in fetal muscle development of pigs

“…The two regions were also synthetic to human HSC 1q32 and 21q21, where human BTG2 and BTG3 gene was assigned, suggesting the reliability of our mapping result. By scanning the two regions in pig QTL (Quantitative Traits Loci) map, we found BTG2 located in putative QTL region correlated with meat quality, production and reproduction traits (Yu et al, 1995;Rohrer et al, 1999;Quintanilla et al, 2002;Milan et al, 2002;Kim et al, 2006), and BTG3 located in putative QTL region associated with meat quality and production traits (Knott et al, 1998;Yue et al, 2003;Ponsuksili et al, 2005). The location of BTG2 and BTG3 gene under QTL regions indicated these two genes may be possible candidate genes for meat production traits.…”