Genes for three different isoforms of transforming growth factor-β are present in plaice (Pleuronectes platessa) DNA

Although transforming growth factor-β (TGF-β) genes have been described in several species of fish, whether an individual fish possesses more than one member of this multigene family has yet to be established. During this study, three DNA fragments were isolated from the plaice (Pleuronectes platessa) by homology cloning. Sequence analysis revealed that each fragment closely resembled a distinct member of the TGF-β family. Each putative plaice TGF-β clustered individually with a different TGF-β subgroup during phylogenetic analysis suggesting that these may be the plaice homologues of vertebrate TGF-β1/4/5, -β2 or -β3. The first direct evidence for the presence of multiple TGF-β genes in a single fish species is presented.