Two cognate hormones, @entity2124 ( @entity2124 ) and somatolactin (SL), control several important physiological processes in vertebrates. Knowledge about @entity2124 and its receptor ( @entity9045 ) has accumulated over the last decades. However, much less is known about SL and its receptor (SLR). SL is found only in fish (including lungfish), suggesting that it was present in the common ancestor of vertebrates, but was lost secondarily in the lineage leading to land vertebrates after the lungfish branched off. SLR was suggested to be a duplicated copy of @entity9045 acquired only in teleosts via the @entity9963 ( @entity9963 ). This scenario (i.e., the existence of SL but not SLR in the vertebrate ancestors) is intriguing but contested. In this study, we first evaluated the plausibility of this scenario through synteny analyses and found that the loci for @entity9045 and SLR are located in syntenic genomic positions, whereas the loci for @entity2124 and SL are not. Next, we cloned GHRs of lungfish and sturgeon, which possess SL but did not undergo the @entity9963 (i.e., they should not possess SLR). Their phylogenetic positions in the @entity9045 /SLR gene tree further support the fish-specific scenario for the @entity9045 -SLR duplication. Interestingly, their sequences share greater similarity with teleost SLRs and reptilian/amphibian GHRs than with the GHRs of mammals, birds, and teleosts. On the basis of these results, we discuss the validity of the nomenclature of the teleost-specific copy of @entity9045 as SLR and an ancestral receptor(s) for SL before the evolution of SLR during the @entity9963 .

Evolution of receptors for XXXX and somatolactin in fish and land vertebrates: lessons from the lungfish and sturgeon orthologues.

@entity2124 :: ('2688', 'Gene') :: ['GH', 'growth hormone'] @entity9963 :: ('MESH:D005393', 'Disease') :: ['FSGD', 'fish-specific genome duplication'] @entity9045 :: ('2690', 'Gene') :: ['GHR']
@entity2124 :: (2688,Gene) :: ['growth hormone']
