All animals come from the sea, and many of them managed to conquer terrestrial environments. The most successful of these lineages are arthropods, including insects, spiders or myriapods. The goal of this project was to understand how arthropods adapted to life on land. However, a series of questions needed to be addressed beforehand. For instance, arthropod phylogeny has been controversial, particularly in some of the lineages. How do different analyses affect the inferred phylogeny, particularly orthology inference? A second important question revolved around understanding how and when genes arose in this lineage. Are most genes ancient? Did they arise recently? And did they evolve through speciation or duplication? I tackled these questions through a bioinformatic spyglass.
Arthropods constitute the most successful animal phylum on our planet. By learning how their genomes evolved, we can hope to further our understanding on how to preserve specific lineages, or how to contain pests. For instance, in one of our publications we investigated how selection affected recent duplicated genes in the pea aphid, Acyrthosiphon pisum, an important pest. We showed that some genes involved in the maintenance of symbiotic relationships with bacteria (key for the aphid since they synthesize some essential amino acids) arose through recent gene duplication, and opens the door to the design of targeted drugs to contain this pest.
Overall objectives:
(1) How did arthropod genes evolve? Are most genes ‘old’ (i.e. gained in the Animal Tree of Life before arthropods arose) or ‘new’ (i.e. lineage-specific)? Did they evolve through speciation or duplication?
(2) How did selection reshaped genes recently duplicated in some arthropod lineages?
Conclusions of the action
- Most arthropod genes are very ancient and date back to the ancestor of animals and their relatives.
- Around one third of the genes in arthropod genomes evolved ‘recently’ (i.e. were gained in the branch leading to the phylum).
- Gene duplication was an important force shaping arthropod genomes, potentially facilitating adaptation to life on land.
- Genes recently duplicated were also important for pests, as in the case of the pea aphid, where recent duplicates facilitate symbiosis with bacteria.
