The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, Maryland 20850, USA. jeisen@tigr.org
The determination and analysis of complete genome sequences have recently enabled many major advances to be made in the area of microbial evolutionary biology. These include the determination of the first genome of a Crenarchaeota, the suggestion that horizontal gene transfer may be the rule rather than the exception, and revelations about how genomes evolve on short timescales.