Transcriptomic correlates of caste differentiation and invasiveness in a subterranean termite
Abstract
Termite colonies are characterized by a division of labour into reproductive and helper castes (soldiers and workers). Caste differentiation is associated with differences in gene expression that reflect developmental and evolutionary origins. I used RNA-seq to investigate genome-wide expression patterns of reproductive nymph, soldier, and worker castes of Reticulitermes flavipes from three populations. I found 93 genes differentially expressed as a function of caste, with the majority of genes being uniquely up-regulated in soldiers. My findings suggest that soldiers evolved genes that are distinct from nymphs and workers, and are signs of possible genomic novelty. I also analyzed this transcriptome as a function of population since R. flavipes is invasive to Canada and display supercolony-like phenotypes such as lack of kin recognition. I found 302 differentially expressed genes, with 77% of these biased toward their invasive-native status. These population gene sets indicate molecular level adaptations to the observed invasive phenotypes.