Meeting Abstract
Animals in the Antarctic seas have adapted to some of the most challenging conditions found anywhere on Earth. Temperatures ranging between 0 and -1.8°C and a food supply which fluctuates widely render their survival difficult. Nevertheless, species have found the means to thrive in such conditions. Sponges are particularly important members of Antarctic ecosystems, but to date our knowledge of how they endure these temperatures is limited at best, especially at a molecular level. We aim to identify the mechanisms by which sponges have adapted to such extreme environments by contrasting congeneric species pairs adapted to vastly differing thermal environments. These aims are being accomplished using transcriptomic and genomic sequences from genera within the Demospongiae. The chosen genera are abundant in the Antarctic, Caribbean and Mediterranean, and play essential roles in the benthic ecosystems in which they are found. Particularly, we have sequenced multiple transcriptomes from 10 target species, as well as the genomes of Mycale acerata and Mycale laevis, and are supplementing our “omic” work with targeted in situ and functional experiments. Using this data, we have performed a number of tests for selection (particularly in Hyphy/CODEML) and identified genes with multiple lines of evidence for positive selection, including a number of phylogenetically well-conserved “housekeeping” genes. We have also analyzed differential gene expression and content. With this data, we can state which genes are vital in cold conditions, and when adaptive molecular mechanisms have been used broadly, convergently, or in vastly varying ways across sponge and animal phylogeny.
