Detection of Quantitative Trait Loci for Backfat Thickness and Intramuscular Fat Content in Pigs (Sus scrofa)

Abstract

In an experimental cross between Meishan and Dutch Large White and Landrace lines, 619 F2 animals and their parents were typed for molecular markers covering the entire porcine genome. Associations were studied between these markers and two fatness traits: intramuscular fat content and backfat thickness. Association analyses were performed using interval mapping by regression under two genetic models: (1) an outbred line-cross model where the founder lines were assumed to be fixed for different QTL alleles; and (2) a half-sib model where a unique allele substitution effect was fitted within each of the 19 half-sib families. Both approaches revealed for backfat thickness a highly significant QTL on chromosome 7 and suggestive evidence for a QTL at chromosome 2. Furthermore, suggestive QTL affecting backfat thickness were detected on chromosomes 1 and 6 under the line-cross model. For intramuscular fat content the line-cross approach showed suggestive evidence for QTL on chromosomes 2, 4, and 6, whereas the half-sib analysis showed suggestive linkage for chromosomes 4 and 7. The nature of the QTL effects and assumptions underlying both models could explain discrepancies between the findings under the two models. It is concluded that both approaches can complement each other in the analysis of data from outbred line crosses.

Genetic Variation of H-FABP Gene and Association with Intramuscular Fat Content in Laiwu Black and Four Western Pig Breeds

“…Breeding objectives for different breeds may have changed the allelic distribution of the H-FABP RFLPs. Previously, Janss et al (1997), De Koning et al (1999) andBo Zuo et al (2003) found some evidence suggestive of QTL and a major gene affecting IMF content. Findings from this study with Laiwu Black and four western breeds support the association of H-FABP genetic variation with intramuscular fat content (Gerbens et al, 1999).…”

La recherche de QTL àl’aide de marqueurs : résultats chez le porc

“…Sur le chromosome 2, le locus de teneur en muscle est localisé dans la région du gène IGF-2, pour laquelle des effets similaires ont été mis en évidence dans des croisements Large White x Piétrain (Nezer et al 1999) et Large White x sanglier (Jeon et al 1999). Des QTL pour les caractères de croissance et l'épaisseur de lard dorsal ont été mis en évidence ou suggérés dans la même région du chromosome 4 par Andersson et al (1994) De même, Wang et al (1998), Rohrer et Keele (1998aet 1998b et de Koning et al (1999) rapportent l'existence d'un QTL d'épaisseur de lard dorsal dans la même région du chromosome 7 que la présente étude. Enfin, un QTL de composition corporelle est également détecté sur le chromosome X par Rohrer et Keele (1998aet 1998b.…”

Identification of Quantitative Trait Loci (QTL) Affecting Teat Number in Pigs

“…Following this, QTL for growth and fat deposition traits (Paszek et al, 1999;Rohrer, 2000;Wada et al, 2000;Bidanel et al, 2001;Malek et al, 2001a), for carcass traits (Andersson-Eklund et al, 1998;Rohrer et al, 1998b), and for meat quality (De Koning et al, 1999Malek et al, 2001b) have been reported. QTL affecting reproduction traits in swine have been reported by Rathje et al (1997) and Wilkie et al (1999).…”