title: Detection of a Cis [corrected] eQTL controlling BCMO1 gene expression leads to the identification of a QTG for chicken breast meat color.
abstract: Classical quantitative trait loci (QTL) analysis and gene expression QTL (eQTL) were combined to identify the causal gene (or QTG) underlying a highly significant QTL controlling the variation of breast meat color in a F2 cross between divergent high-growth (HG) and low-growth (LG) chicken lines. Within this meat quality QTL, BCMO1 (Accession number GenBank: AJ271386), encoding the β-carotene 15, 15'-monooxygenase, a key enzyme in the conversion of β-carotene into colorless retinal, was a good functional candidate. Analysis of the abundance of BCMO1 mRNA in breast muscle of the HG x LG F2 population allowed for the identification of a strong cis eQTL. Moreover, reevaluation of the color QTL taking BCMO1 mRNA levels as a covariate indicated that BCMO1 mRNA levels entirely explained the variations in meat color. Two fully-linked single nucleotide polymorphisms (SNP) located within the proximal promoter of BCMO1 gene were identified. Haplotype substitution resulted in a marked difference in BCMO1 promoter activity in vitro. The association study in the F2 population revealed a three-fold difference in BCMO1 expression leading to a difference of 1 standard deviation in yellow color between the homozygous birds at this haplotype. This difference in meat yellow color was fully consistent with the difference in carotenoid content (i.e. lutein and zeaxanthin) evidenced between the two alternative haplotypes. A significant association between the haplotype, the level of BCMO1 expression and the yellow color of the meat was also recovered in an unrelated commercial broiler population. The mutation could be of economic importance for poultry production by making possible a gene-assisted selection for color, a determining aspect of meat quality. Moreover, this natural genetic diversity constitutes a new model for the study of β-carotene metabolism which may act upon diverse biological processes as precursor of the vitamin A.
authors.affiliation: INRA, UR83, Recherches Avicoles, Nouzilly, France. lebihan@tours.inra.fr
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Le Bihan-Duval
authors.forename: Javad
authors.initials: J
authors.lastname: Nadaf
authors.forename: Cécile
authors.initials: C
authors.lastname: Berri
authors.forename: Frédérique
authors.initials: F
authors.lastname: Pitel
authors.forename: Benoît
authors.initials: B
authors.lastname: Graulet
authors.forename: Estelle
authors.initials: E
authors.lastname: Godet
authors.forename: Sophie Y
authors.initials: SY
authors.lastname: Leroux
authors.forename: Olivier
authors.initials: O
authors.lastname: Demeure
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lagarrigue
authors.forename: Cécile
authors.initials: C
authors.lastname: Duby
authors.forename: Larry A
authors.initials: LA
authors.lastname: Cogburn
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Beaumont
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Duclos
mesh_terms: D000818:Animals; D001947:Breeding; D002338:Carotenoids / Q000378:metabolism; D045744:Cell Line, Tumor; D002645:Chickens / Q000235:genetics*; D002874:Chromosome Mapping; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D008460:Meat; D009132:Muscles / Q000378:metabolism; D009154:Mutation; D010858:Pigmentation / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D050559:beta-Carotene 15,15'-Monooxygenase / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D002338:Carotenoids; D008156:Luciferases; D050559:beta-Carotene 15,15'-Monooxygenase