Polar diatoms
Solid3 reads of the genome of Attheya sp. (CCMP212) and Amphora sp. (CCMP2378)
Sea ice diatoms are among the most successful algae in polar regions, accounting for up to 30% of primary productivity in these regions. About 200 species are known to inhabit sea ice, one of the most inhospitable environments on earth, where freezing temperatures, high salinity and low light are common.  What are the factors that have allowed for their remarkable success? Many of the secrets are locked away in their genomes. This study focuses on a family of genes that encode ice-binding proteins (IBPs), which appear to be critical to the success of diatoms and other species of algae in polar regions. These proteins are released into the extracellular environment where they appear to preserve liquid environments that are essential for microbial survival in ice.  Preliminary evidence suggests that the IBP genes are abundant and diverse within the genomes of single species, a possible reflection of their importance. In addition, IBP genes are curiously absent from the genomes of nonpolar species, while several IBP homologs have been found in ice-adapted bacteria and fungi. This raises the possibility that the algal IBPs were acquired by horizontal gene transfer from bacteria or fungi. To examine these possibilities, the genomes of two species of sea ice diatom, Attheya sp. (CCMP212) and Amphora sp. (CCMP2378) were sequenced with the Solid3 system, providing approximately 40 million 50-nt reads for each species. The data will be used to determine the diversity and abundance of algal IBPs, and their phylogenetic relationships with bacterial and fungal IBPs. These results should greatly clarify the role and origins of algal IBPs, and thus the evolutionary steps that allowed them to colonize the polar regions. There is presently a large research community working on algal evolution and biology, largely through genomic analyses. The present sequence data will be of useful for many of these projects.