Authors: Remington R Motte
Mentors: Carl Hjelmen
Insitution: Utah Valley University
Down Syndrome Cell Adhesion Molecule (DSCAM, an immunoglobulin protein) is a protein that is important for neuronal development, especially in invertebrates. While DSCAM is present in other organisms, it has gone through multiple independent duplication events in arthropods. This has resulted in four to six DSCAM exon clusters with thousands of isoforms throughout arthropoda. Due to DSCAM’s role in brain development, I investigated DSCAM1 evolution and its relationship to the evolution of sociality in arthropods. I defined eusocial as having a common nest, cooperative brood care, reproductive castes and generational overlap. Any species that exhibited one or some of these traits I categorized as sub-social, and any that didn’t show these traits were categorized as solitary. Using Bayesian phylogenetic techniques, I compared DSCAM1 phylogenies to mitochondrion phylogenies and found higher rates of evolution in the DSCAM gene within Hymenoptera. The same increased rates were not found with other eusocial species. I then mapped sociality status onto phylogenies to visualize patterns of evolution and estimate ancestral condition of sociality for common ancestors. Increased taxon sampling within cockroaches and termites (Blattodea), as well as including ambrosia beetles (Austroplatypus incompertus), aphids (Pemphigus spyrothecae) and thrips (Kladothrips) could elucidate the relationship between DSCAM evolution and sociality in arthropods.