Meeting Abstract
The repeated evolution of convergent morphologies in cave adapted organisms, across widely divergent taxonomic groups, has long fascinated biologists. Evolving to live in the absence of light, many cave organisms are blind with reduced or absent eyes, yet genes involved in light-interaction and eye development are often still intact in the genome. This suggests that evolutionary and developmental changes in gene regulation may be responsible for the observed phenotypes. Freshwater crayfish present an excellent system to study this phenomenon in a phylogenetic framework. The phylogeny of the group is relatively well understood and a number of independent lineages have invaded caves at different points in time and in different geographic locations. This provides evolutionarily independent replicates of the process, increasing the power of comparative analyses. Additionally, many genes in involved in phototransduction, circadian rhythms and eye development have been identified in related organisms, facilitating transcriptome annotation and PCR primer design. We used RNA-seq to compare eye transcriptomes of cave and surface crayfish. We then identified differentially expressed genes, taking into account phylogeny and intra-specific variation. Candidate genes involved in vision loss will be used in a greater phylogenetic context to reveal how evolutionary changes in gene expression result in convergent phenotypes in cave organisms and further unravel the genetic mechanisms of vision in decapod crustaceans.
