title: Receptors rather than signals change in expression in four physiological regulatory networks during evolutionary divergence in threespine stickleback.
abstract: The molecular mechanisms underlying behavioural evolution following colonization of novel environments are largely unknown. Molecules that interact to control equilibrium within an organism form physiological regulatory networks. It is essential to determine whether particular components of physiological regulatory networks evolve or if the network as a whole is affected in populations diverging in behavioural responses, as this may affect the nature, amplitude and number of impacted traits. We studied the regulation of four physiological regulatory networks in freshwater and marine populations of threespine stickleback raised in a common environment, which were previously characterized as showing evolutionary divergence in behaviour and stress reactivity. We measured nineteen components of these networks (ligands and receptors) using mRNA and monoamine levels in the brain, pituitary and interrenal gland, as well as hormone levels. Freshwater fish showed higher expression in the brain of adrenergic (adrb2a), serotonergic (htr2a) and dopaminergic (DRD2) receptors, but lower expression of the htr2b receptor. Freshwater fish also showed higher expression of the mc2r receptor of the glucocorticoid axis in the interrenals. Collectively, our results suggest that the inheritance of the regulation of these networks may be implicated in the evolution of behaviour and stress reactivity in association with population divergence. Our results also suggest that evolutionary change in freshwater threespine stickleback may be more associated with the expression of specific receptors rather than with global changes of all the measured constituents of the physiological regulatory networks.
authors.affiliation: Département de Biologie & Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Quebec, Canada, G1V 0A6.
authors.forename: Carole
authors.initials: C
authors.lastname: Di Poi
authors.affiliation: Département de Sciences Biologiques, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7.
authors.forename: Dominic
authors.initials: D
authors.lastname: Bélanger
authors.affiliation: Département de Sciences Biologiques, Université de Montréal, Montréal, Quebec, Canada, H3C 3J7.
authors.forename: Marc
authors.initials: M
authors.lastname: Amyot
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4.
authors.forename: Sean
authors.initials: S
authors.lastname: Rogers
authors.affiliation: Département de Biologie & Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Quebec, Canada, G1V 0A6.
authors.forename: Nadia
authors.initials: N
authors.lastname: Aubin-Horth
mesh_terms: D000818:Animals; D015306:Biogenic Monoamines / Q000032:analysis; D004777:Environment; D019143:Evolution, Molecular; D053263:Gene Regulatory Networks; D006854:Hydrocortisone / Q000032:analysis; D017982:Receptors, Biogenic Amine / Q000235:genetics*; D011965:Receptors, Glucocorticoid / Q000235:genetics*; D023701:Smegmamorpha / Q000235:genetics* / Q000502:physiology
chemical_list: D015306:Biogenic Monoamines; D017982:Receptors, Biogenic Amine; D011965:Receptors, Glucocorticoid; D006854:Hydrocortisone
keywords: behaviour; evolution; gene expression; hormones; monoamines; physiological regulatory networks