page_title: Teleost leptins
section_title: Examples
hierarchical_section_title: Teleost leptins / Examples
caption_attribution_description: English: . Phylogenetic tree of vertebrate leptins
context_page_description: Teleost leptins are a family of peptide hormones found in fish that are orthologs of the mammalian hormone leptin. The teleost and mammalian leptins appear to have similar functions, namely, regulation of energy intake and expenditure.
  The leptin hormone was long thought to be specific to mammals, but in recent years the gene has been found in amphibia such as the tiger salamander, and the African clawed frog. The discovery of lep in puffer fish demonstrates the ancient ancestry of this hormone.
context_section_description: There are two closely related lep paralogues in Atlantic salmon (Salmo salar).  A single lep gene has been documented for green-spotted pufferfish (Tetraodon nigroviridis), rainbow trout (Oncorhynchus mykiss), Arctic charr (Salvelinus alpinus), silver carp (Hypophthalmichthys molitrix), and grass carp (Ctenopharyngodon idellus). In other species there are reports of two closely related lep paralogues, including common carp (Cyprinus carpio) and Atlantic salmon. More distantly related lep genes have been found in medaka (Oryzias latipes) and zebrafish (Danio rerio). At least 2 leptin genes (lepa and lepb) exist in the crown-clade (Fig. 1). Early findings have shown that lepa and lepb share low interspecies aa identity, and are argued to have arisen through whole genome duplication, which occurred early in the teleost lineage. The duplicity of genes has been described for Atlantic salmon, Japanese medaka, common carp and zebrafish. Both lep paralogues cluster with lepa, and therefore suggest that at least one or more form (lepb) may exist in this species, since it is tetraploid.  However, previous attempts using genomic synteny have only found the putative genomic duplicates in medaka and zebrafish paralogue. Currently it remains unclear, whether lepb exists in other teleosts due to the degenerative nature of this paralogue.
caption: Figure 1. Phylogenetic tree of vertebrate leptins
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