Those complexes, in which gene-order remains conserved over evolutionary time, are likely to be constrained by factors such as coordinated regulation (as in the case of the Hox and E(Spl)-C). The syntenic sHSP-C is present in most insect genomes, and its conserved coordinate expression and regulation implies that it is an integral genomic component of environmental response in arthropods.Įvolutionary conserved syntenic gene complexes are relatively rare in arthropod genomes, with only three major well-characterised examples, the Hox complex, the E(spl)-C and the runt complex represented in the majority of arthropod lineages. Finally we have shown that the honeybee sHSP-C is co-ordinately expressed and is marked by genomic features, including H3K27me3 histone marks consistent with coordinate regulation, during honeybee ovary activation. Using 11 genomes from Hymenopteran species our phylogenetic analyses have refined the evolution of the sHSP-C in Hymenoptera and found that the sHSP-C is order-specific with evidence of birth-and-death evolution in the hymenopteran lineage. Using eight genomes from representative insect orders and three non-insect arthropod genomes we have identified that a syntenic cluster of sHSPs (sHSP-C) is a hallmark of most Arthropod genomes. Previous phylogenetic analyses of these clustered sHSP have been limited to a small number of holometabolous insect species and have not determined the pattern of evolution of the clustered sHSP genes (sHSP-C) in insect or Arthropod lineages.
Numerous sHSPs have been identified in the genomes of insects, some of which are located clustered in close proximity. Conserved syntenic gene complexes are rare in Arthropods and likely only retained due to functional constraint.