Social bacteria and asocial eukaryotes

The end of 2007 brought us draft genome sequences of two eukaryotic microorganisms, Babesia bovis and Malassezia globosa, as well as complete genomes of the ammonia-oxidizing archaeal chemoautotroph Nitrosopumilus maritimus, and several environmental bacteria (Table 1). In terms of genome size, this list covers both sides of the spectrum: the 245 kb genome of an obligate insect symbiont Sulcia muelleri is the second smallest microbial genome sequenced so far, whereas the 13 033 kb chromosome of the social myxobacterium Sorangium cellulosum breaks the record as the largest bacterial genome – and the largest DNA molecule in the prokaryotic world.