title: Identification of the orphan gene Prod 1 in basal and other salamander families.
abstract: BACKGROUND
  The urodele amphibians (salamanders) are the only adult tetrapods able to regenerate the limb. It is unclear if this is an ancestral property that is retained in salamanders but lost in other tetrapods or if it evolved in salamanders. The three-finger protein Prod 1 is implicated in the mechanism of newt limb regeneration, and no orthologs have been found in other vertebrates, thus providing evidence for the second viewpoint. It has also been suggested that this protein could play a role in salamander-specific aspects of limb development. There are ten families of extant salamanders, and Prod 1 has only been identified in two of them to date. It is important to determine if it is present in other families and, particularly, the basal group of two families which diverged approximately 200 MYA.
  
  
  RESULTS
  We have used polymerase chain reaction (PCR) to identify Prod 1 in a Chinese hynobiid species Batrachuperus longdongensis. We obtained an intestinal transcriptome of the plethodontid Aneides lugubris and, from this, identified a primer which allowed PCR of two Prod 1 genes from this species. All known Prod 1 sequences from nine species in four families have been aligned, and a phylogenetic tree has been derived.
  
  
  CONCLUSIONS
  Prod 1 is found in basal salamanders of the family Hynobiidae, and in at least three other families, so it may be present in all extant salamanders. It remains a plausible candidate to have been involved in the origins of limb regeneration, as well as the apomorphic aspects of limb development.
authors: State Key Laboratory of Biocontrol, College of Ecology and Evolution, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510006 China.
authors: Jie
authors: J
authors: Geng
authors: Institute of Structural and Molecular Biology, Division of Biosciences, UCL, Gower Street, London, WC1E 6BT UK.
authors: Phillip B
authors: PB
authors: Gates
authors: Institute of Structural and Molecular Biology, Division of Biosciences, UCL, Gower Street, London, WC1E 6BT UK.
authors: Anoop
authors: A
authors: Kumar
authors: Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
authors: Stefan
authors: S
authors: Guenther
authors: National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA UK.
authors: Acely
authors: A
authors: Garza-Garcia
authors: Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
authors: Carsten
authors: C
authors: Kuenne
authors: State Key Laboratory of Biocontrol, College of Ecology and Evolution, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510006 China.
authors: Peng
authors: P
authors: Zhang
authors: Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
authors: Mario
authors: M
authors: Looso
authors: Institute of Structural and Molecular Biology, Division of Biosciences, UCL, Gower Street, London, WC1E 6BT UK.
authors: Jeremy P
authors: JP
authors: Brockes
keywords: Hynobiid; Limb regeneration; Phylogeny; Plethodontid; Three-finger protein