title: Reconciling the deep homology of neuromodulation with the evolution of behavior.
abstract: The evolution of behavior seems inconsistent with the deep homology of neuromodulatory signaling. G protein coupled receptors (GPCRs) evolved slowly from a common ancestor through a process involving gene duplication, neofunctionalization, and loss. Neuropeptides co-evolved with their receptors and exhibit many conserved functions. Furthermore, brain areas are highly conserved with suggestions of deep anatomical homology between arthropods and vertebrates. Yet, behavior evolved more rapidly; even members of the same genus or species can differ in heritable behavior. The solution to the paradox involves changes in the compartmentalization, or subfunctionalization, of neuromodulation; neurons shift their expression of GPCRs and the content of monoamines and neuropeptides. Furthermore, parallel evolution of neuromodulatory signaling systems suggests a route for repeated evolution of similar behaviors.
authors.affiliation: Neuroscience Institute, Georgia State University, PO Box 5030, Atlanta, GA 30302, United States. Electronic address: pkatz@gsu.edu.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Katz
authors.affiliation: Janelia Farm Research Campus, Howard Hughes Medical Institute, United States.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Lillvis
mesh_terms: D000818:Animals; D001519:Behavior; D005075:Biological Evolution; D006801:Humans; D009479:Neuropeptides / Q000737:chemistry / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000737:chemistry / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D009479:Neuropeptides; D018377:Neurotransmitter Agents