| Summary: | <p>Abstract</p> <p>Background</p> <p>Somatostatin and its related neuroendocrine peptides have a wide variety of physiological functions that are mediated by five somatostatin receptors with gene names <it>SSTR1-5</it> in mammals. To resolve their evolution in vertebrates we have investigated the SSTR genes and a large number of adjacent gene families by phylogeny and conserved synteny analyses in a broad range of vertebrate species.</p> <p>Results</p> <p>We find that the SSTRs form two families that belong to distinct paralogons. We observe not only chromosomal similarities reflecting the paralogy relationships between the SSTR-bearing chromosome regions, but also extensive rearrangements between these regions in teleost fish genomes, including fusions and translocations followed by reshuffling through intrachromosomal rearrangements. These events obscure the paralogy relationships but are still tractable thanks to the many genomes now available. We have identified a previously unrecognized SSTR subtype, <it>SSTR6</it>, previously misidentified as either <it>SSTR1</it> or <it>SSTR4.</it></p> <p>Conclusions</p> <p>Two ancestral SSTR-bearing chromosome regions were duplicated in the two basal vertebrate tetraploidizations (2R). One of these ancestral SSTR genes generated <it>SSTR2, -3</it> and -<it>5</it>, the other gave rise to <it>SSTR1, -4</it> and -<it>6</it>. Subsequently <it>SSTR6</it> was lost in tetrapods and <it>SSTR4</it> in teleosts. Our study shows that extensive chromosomal rearrangements have taken place between related chromosome regions in teleosts, but that these events can be resolved by investigating several distantly related species.</p>
|
|---|
