title: Insulin-like growth factor-I gene polymorphism associations with growth, body composition, skeleton integrity, and metabolic traits in chickens.
abstract: Molecular genetic selection on individual genes is a promising method to genetically improve economically important traits in chickens. A resource population was developed to study the genetics of growth, body composition, skeletal integrity, and metabolism traits. Broiler sires were crossed to dams of 2 diverse, highly inbred lines (Leghorn and Fayoumi), and the F1 birds were intermated by dam line to produce broiler-Leghorn and broiler-Fayoumi F2 offspring. Growth, body composition, skeletal integrity, and hormonal and metabolic factors were measured in 713 F2 individuals. Insulin-like growth factor-I (IGF1) was selected for study as a biological and positional candidate gene. A single nucleotide polymorphism (SNP) was identified between the founder lines in the IGF1 promoter region, and a PCR-RFLP assay was developed. A mixed model was used to statistically analyze associations of IGF1-SNP1 with phenotypic traits. The IGF1-SNP1 had significant associations with most recorded traits, except metabolic traits. Strong interactions between the IGF1 gene and genetic background on growth traits in the 2 F2 populations suggest that genetic interaction is an important aspect for consideration before using the IGF1-SNP1 in marker-assisted selection programs. Several beneficial effects (improved growth, increased breast muscle weight, decreased abdominal fat, and enhanced skeletal integrity) associated with 1 allele indicate the presence of 1 or more loci near IGF1-SNP1 controlling biologically diverse and economically important traits in chickens.
authors.affiliation: Department of Animal Science, Iowa State University, Ames, Iowa 50011-3150, USA.
authors.forename: H
authors.initials: H
authors.lastname: Zhou
authors.forename: A D
authors.initials: AD
authors.lastname: Mitchell
authors.forename: J P
authors.initials: JP
authors.lastname: McMurtry
authors.forename: C M
authors.initials: CM
authors.lastname: Ashwell
authors.forename: S J
authors.initials: SJ
authors.lastname: Lamont
mesh_terms: D000818:Animals; D001823:Body Composition / Q000235:genetics / Q000502:physiology; D001842:Bone and Bones / Q000502:physiology; D002645:Chickens / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005260:Female; D005838:Genotype; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012737:Sex Factors
chemical_list: D007334:Insulin-Like Growth Factor I