title: Quack leptin.
abstract: BACKGROUND
  A LEP transcript up-regulated in lungs of ducks (Anas platyrhynchos) infected by avian influenza A virus was recently described in the Nature Genetics manuscript that reported the duck genome. In vertebrates, LEP gene symbol is reserved for leptin, the key regulator of energy balance in mammals.
  
  
  RESULTS
  Launching an extensive search for this gene in the genome data that was submitted to the public databases along with duck genome manuscript and extending this search to all avian genomes in the whole-genome shotgun-sequencing database, we were able to report the first identification of coding sequences capable of encoding the full leptin protein precursor in wild birds. Gene structure, synteny and sequence-similarity (up to 54% identity and 68% similarity) to reptilian leptin evident in falcons (Falco peregrinus and cherrug), tits (Pseudopodoces humilis), finches (Taeniopygia guttata) and doves (Columba livia) confirmed that the bird leptin was a true ortholog of its mammalian form. Nevertheless, in duck, like other domestic fowls the LEP gene was not identifiable.
  
  
  CONCLUSIONS
  Lack of the LEP gene in poultry suggests that birds that have lost it are particularly suited to domestication. Identification of an intact avian gene for leptin in wild birds might explain in part the evolutionary conservation of its receptor in leptin-less fowls.
authors.forename: Miriam
authors.initials: M
authors.lastname: Friedman-Einat
authors.affiliation: Institute of Animal Science, The Volcani Center, Rishon Le-Zion, Israel. seroussi@agri.huji.ac.il.
authors.forename: Eyal
authors.initials: E
authors.lastname: Seroussi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004372:Ducks / Q000235:genetics*; D020738:Leptin / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D026801:Synteny
chemical_list: D030161:Avian Proteins; D020738:Leptin