Research paperAllatostatins C, double C and triple C, the result of a local gene triplication in an ancestral arthropod

- Local gene duplications in an ancestral arthropod created three allatostatin C genes.
- These three genes code for three different peptides, allatostatin C, CC and CCC.
- Horse shoe crabs, spiders, scorpions, myriapods and decapods have all three genes.
- Most insects lost one gene, but migratory locusts and sawflies have still all three.
- Some arthropods genome assemblies have contigs with all three genes still associated.

Allatostatin C is the arthropod homolog of vertebrate somatostatin. The gene went through a local gene triplification leading to the existence of three genes coding such peptides, allatostatins C, CC and CCC. All three genes are still present in several chelicerates, such as the horseshoe crab Limulus polyphemus, several spiders and the scorpion Mesobuthus martensii, the myriapod Strigamia maritima, as well as at least two insect species, Locusta migratoria and Athalia rosae, a sawfly. All three peptides have well conserved primary structures and peptides can easily be classified as either allatostatin C, CC or CCC. In most insect species only two of the genes have been preserved. In many species, these are CC and CCC, but in Diptera, Lepidoptera and Coleoptera it are allatostatins C and CC that are still present. In some arthropod species two or even all three genes can still be found closely associated in the genome and are present on the same scaffold showing that a local amplification was at the origin of these genes.