Meeting Abstract
Freshwater crayfishes have evolved to live in caves from surface ancestors independently at different point in the group’s evolutionary history, resulting in replicated events of vision loss. This allows us to identify genes that are repeatedly associated with vision loss, ask to what degree evolution takes the same genetic route to vision loss and test if those changes are adaptive in nature. To this end, we take a comparative transcriptomics approach, specifically exploring how evolutionary changes to the transcriptome result in this convergent loss of vision. Using RNA-seq data generated from the eyes of 8 cave and 6 surface species, we identified several thousand homologous gene families expressed. We then tested if expression patterns across these genes were more similar within habitat type or within clades to ask if there are unique gene expression patterns in different cave adapted lineages. We also took a phylogenetic approach to identify a core set of genes associated with vision loss as well as genes uniquely differentially expressed in different instances of vision loss. Finally, we identified genes that displayed a signature of adaptive gene expression variation in the eyes of these species. We found that overall gene expression patterns are more similar among closely related species than they are among distantly related blind or sighted species and that there is a set of genes that are repeatedly associated with vision loss. These results suggest that while the major of gene expression evolution is highly divergent among blind species, there is a set of genes whose expression may be driving the convergent vision loss evolution in this group.
