title: Quantitative Trait Locus and Genetical Genomics Analysis Identifies Putatively Causal Genes for Fecundity and Brooding in the Chicken.
abstract: Life history traits such as fecundity are important to evolution because they make up components of lifetime fitness. Due to their polygenic architectures, such traits are difficult to investigate with genetic mapping. Therefore, little is known about their molecular basis. One possible way toward finding the underlying genes is to map intermediary molecular phenotypes, such as gene expression traits. We set out to map candidate quantitative trait genes for egg fecundity in the chicken by combining quantitative trait locus mapping in an advanced intercross of wild by domestic chickens with expression quantitative trait locus mapping in the same birds. We measured individual egg fecundity in 232 intercross chickens in two consecutive trials, the second one aimed at measuring brooding. We found 12 loci for different aspects of egg fecundity. We then combined the genomic confidence intervals of these loci with expression quantitative trait loci from bone and hypothalamus in the same intercross. Overlaps between egg loci and expression loci, and trait-gene expression correlations identify 29 candidates from bone and five from hypothalamus. The candidate quantitative trait genes include fibroblast growth factor 1, and mitochondrial ribosomal proteins L42 and L32. In summary, we found putative quantitative trait genes for egg traits in the chicken that may have been affected by regulatory variants under chicken domestication. These represent, to the best of our knowledge, some of the first candidate genes identified by genome-wide mapping for life history traits in an avian species.
authors.affiliation: AVIAN Behavioural Genomics and Physiology Group, Dept of Biology, Linköping University, 58183 Linköping, Sweden.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0003-1262-4585
authors.initials: M
authors.lastname: Johnsson
authors.affiliation: Department of Surgical Sciences, Orthopaedics, Uppsala University Hospital, 751 85 Uppsala, Sweden.
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Jonsson
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Andersson
authors.affiliation: AVIAN Behavioural Genomics and Physiology Group, Dept of Biology, Linköping University, 58183 Linköping, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Jensen
authors.affiliation: AVIAN Behavioural Genomics and Physiology Group, Dept of Biology, Linköping University, 58183 Linköping, Sweden domwright@gmail.com.
authors.forename: Dominic
authors.initials: D
authors.lastname: Wright
mesh_terms: D000818:Animals; D001842:Bone and Bones; D002645:Chickens / Q000235:genetics*; D002874:Chromosome Mapping; D004531:Eggs; D005260:Female; D005298:Fertility / Q000235:genetics*; D056726:Genetic Association Studies; D023281:Genomics / Q000379:methods; D007031:Hypothalamus; D008297:Male; D010641:Phenotype; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable
keywords: QTL; brooding; chicken; eQTL; egg; fecundity; genetical genomics