title: The Effect of a Mutation in the Thyroid Stimulating Hormone Receptor (TSHR) on Development, Behaviour and TH Levels in Domesticated Chickens.
abstract: The thyroid stimulating hormone receptor (TSHR) has been suggested to be a "domestication locus" in the chicken, due to a strong selective sweep over the gene found in domesticated chickens, differentiating them from their wild ancestor the Red Junglefowl (RJF). We investigated the effect of the mutation on development (incubation time), behaviour and thyroid hormone levels in intercross chickens homozygous for the mutation (d/d), wild type homozygotes (w/w) or heterozygotes (d/w). This allowed an assessment of the effect of genotype at this locus against a random mix of RJF and WL genotypes throughout the rest of the genome, controlling for family effects. The d/d genotype showed a longer incubation time, less fearful behaviours, lower number of aggressive behaviours and decreased levels of the thyroid hormone T4, in comparison to the w/w genotype. The difference between TSHR genotypes (d/d vs. w/w) in these respects mirrors the differences in development and behaviour between pure domesticated White Leghorns and pure RJF chickens. Higher individual T3 and T4 levels were associated with more aggression. Our study indicates that the TSHR mutation affects typical domestication traits, possibly through modifying plasma levels of thyroid hormones, and may therefore have been important during the evolution of the domestic chicken.
authors.affiliation: IFM Biology, Division of Zoology, Linköping University, SE-581 83 Linköping Sweden.
authors.forename: Anna-Carin
authors.initials: AC
authors.lastname: Karlsson
authors.affiliation: IFM Biology, Division of Zoology, Linköping University, SE-581 83 Linköping Sweden.
authors.forename: Frida
authors.initials: F
authors.lastname: Svemer
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, SE-751 23 Uppsala, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Eriksson
authors.affiliation: Laboratory of Comparative Endocrinology, Department of Biology, Division of Animal Physiology and Neurobiology, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Veerle M
authors.initials: VM
authors.lastname: Darras
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, SE-751 23 Uppsala, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Andersson
authors.affiliation: IFM Biology, Division of Zoology, Linköping University, SE-581 83 Linköping Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Jensen
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D001522:Behavior, Animal; D002645:Chickens / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D005838:Genotype; D008297:Male; D009154:Mutation; D011989:Receptors, Thyrotropin / Q000235:genetics*; D013963:Thyroid Hormones
chemical_list: D011989:Receptors, Thyrotropin; D013963:Thyroid Hormones