title: Comparative analysis reveals loss of the appetite-regulating peptide hormone ghrelin in falcons.
abstract: Ghrelin and leptin are key peripherally secreted appetite-regulating hormones in vertebrates. Here we consider the ghrelin gene (GHRL) of birds (class Aves), where it has been reported that ghrelin inhibits rather than augments feeding. Thirty-one bird species were compared, revealing that most species harbour a functional copy of GHRL and the coding region for its derived peptides ghrelin and obestatin. We provide evidence for loss of GHRL in saker and peregrine falcons, and this is likely to result from the insertion of an ERVK retrotransposon in intron 0. We hypothesise that the loss of anorexigenic ghrelin is a predatory adaptation that results in increased food-seeking behaviour and feeding in falcons.
authors.affiliation: Ghrelin Research Group, Translational Research Institute - Institute of Health and Biomedical Innovation, Queensland University of Technology, 37 Kent St., Woolloongabba, Queensland 4102, Australia; Australian Prostate Cancer Research Centre - Queensland, Queensland University of Technology and Princess Alexandra Hospital, Woolloongabba, Queensland 4102, Australia.
authors.forename: Inge
authors.initials: I
authors.lastname: Seim
authors.affiliation: Ghrelin Research Group, Translational Research Institute - Institute of Health and Biomedical Innovation, Queensland University of Technology, 37 Kent St., Woolloongabba, Queensland 4102, Australia; Australian Prostate Cancer Research Centre - Queensland, Queensland University of Technology and Princess Alexandra Hospital, Woolloongabba, Queensland 4102, Australia.
authors.forename: Penny L
authors.initials: PL
authors.lastname: Jeffery
authors.affiliation: Ghrelin Research Group, Translational Research Institute - Institute of Health and Biomedical Innovation, Queensland University of Technology, 37 Kent St., Woolloongabba, Queensland 4102, Australia; Australian Prostate Cancer Research Centre - Queensland, Queensland University of Technology and Princess Alexandra Hospital, Woolloongabba, Queensland 4102, Australia.
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Herington
authors.affiliation: Ghrelin Research Group, Translational Research Institute - Institute of Health and Biomedical Innovation, Queensland University of Technology, 37 Kent St., Woolloongabba, Queensland 4102, Australia; Australian Prostate Cancer Research Centre - Queensland, Queensland University of Technology and Princess Alexandra Hospital, Woolloongabba, Queensland 4102, Australia. Electronic address: l.chopin@qut.edu.au.
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Chopin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001069:Appetite Regulation / Q000502:physiology*; D046093:Falconiformes / Q000502:physiology*; D054439:Ghrelin / Q000378:metabolism*; D008969:Molecular Sequence Data; D036361:Peptide Hormones / Q000378:metabolism*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones
keywords: Birds; Evolution; Ghrelin; Peptide hormone; Retrotransposon