New evolutionary frontiers from unusual virus genomes
The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20854, USA
Genome Biology 2005, 6:212 doi:10.1186/gb-2005-6-3-212Published: 2 March 2005
The sequences of two giant viral genomes, Mimivirus and a polydnavirus, have recently been published. Mimivirus has the largest known viral genome and encodes an unprecedented number of proteins, whereas the polydnavirus genome has an extremely low coding density and does not encode DNA-replication proteins. These and other unusual features challenge the way we view the evolution and definition of viruses.