title: Test for positional candidate genes for body composition on pig chromosome 6.
abstract: One QTL affecting backfat thickness (BF), intramuscular fat content (IMF) and eye muscle area (MA) was previously localized on porcine chromosome 6 in an F2 cross between Iberian and Landrace pigs. This work was done to study the effect of two positional candidate genes on these traits: H-FABP and LEPR genes. The QTL mapping analysis was repeated with a regression method using genotypes for seven microsatellites and two PCR-RFLPs in the H-FABP and LEPR genes. H-FABP and LEPR genes were located at 85.4 and 107 cM respectively, by linkage analysis. The effects of the candidate gene polymorphisms were analyzed in two ways. When an animal model was fitted, both genes showed significant effects on fatness traits, the H-FABP polymorphism showed significant effects on IMF and MA, and the LEPR polymorphism on BF and IMF. But when the candidate gene effect was included in a QTL regression analysis these associations were not observed, suggesting that they must not be the causal mutations responsible for the effects found. Differences in the results of both analyses showed the inadequacy of the animal model approach for the evaluation of positional candidate genes in populations with linkage disequilibrium, when the probabilities of the parental origin of the QTL alleles are not included in the model.
authors.affiliation: Departamento de Mejora Genética Animal, SGIT-INIA, 28040 Madrid, Spain. ovilo@inia.es
authors.forename: Cristina
authors.initials: C
authors.lastname: OVilo
authors.forename: Angels
authors.initials: A
authors.lastname: Oliver
authors.forename: José Luis
authors.initials: JL
authors.lastname: Noguera
authors.forename: Alex
authors.initials: A
authors.lastname: Clop
authors.forename: Carmen
authors.initials: C
authors.lastname: Barragán
authors.forename: Luis
authors.initials: L
authors.lastname: Varona
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodríguez
authors.forename: Miguel
authors.initials: M
authors.lastname: Toro
authors.forename: Armand
authors.initials: A
authors.lastname: Sánchez
authors.forename: Miguel
authors.initials: M
authors.lastname: Pérez-Enciso
authors.forename: Luis
authors.initials: L
authors.lastname: Silió
mesh_terms: D000818:Animals; D001823:Body Composition / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics*; D050556:Fatty Acid-Binding Proteins; D014644:Genetic Variation; D005838:Genotype; D015810:Linkage Disequilibrium / Q000235:genetics; D008055:Lipids / Q000032:analysis; D018895:Microsatellite Repeats / Q000235:genetics; D008957:Models, Genetic; D009363:Neoplasm Proteins; D012150:Polymorphism, Restriction Fragment Length; D019655:Quantitative Trait, Heritable; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D012044:Regression Analysis; D013552:Swine / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D008055:Lipids; D009363:Neoplasm Proteins; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin