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Representation of the five classes of viral genes in three selected viruses with small, medium-size and large genomes |
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| Genome size (kb)/number of annotated genes |
Representation of the 5 classes of viral genes (number and brief description) |
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| 1. Recent acquisitions from cells |
2. Ancient acquisitions from cells |
3. ORFans |
4. Conserved virus-specific genes |
5. Hallmark genes |
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| Virus |
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| Poliovirusa |
7.4/10 |
None |
2: a duplication of a chymotrypsin-like protease (3C, 2A) |
1: uncharacterized protein (3A) |
1: genome-linked protein (VPg) |
6: 4 diverged copies of JRC (VP1-4), S3H (3C), RdRp (3D) |
| Sulfolobus turreted icosahedral virus (STIV)b |
17.6/36 |
3: two predicted transcription regulators and an uncharacterized protein |
5: four predicted transcription regulators and an uncharacterized protein |
26: uncharacterized proteins |
None |
2: JRC, packaging ATPase |
| Vaccinia virusc |
194.7/~200 |
~48: primarily, proteins involved in virus-host interaction |
~36: primarily, proteins involved in genome replication and expression |
~24: poorly characterized proteins, possibly, involved in virus-host interactions |
~84: primarily, structural components of the virion and some proteins involved in genome expression |
5: JRC, S3H/primase, packaging ATPase, DNA polymerase(?) |
|
aThe classification is based on the analysis described in [87]. bThe classification is based on the analysis described in [11]. cThe classification is based on the analysis described in [108] and EVK, unpublished observations; the uncertainty in the number of genes is due to the pseudogenization of varying subsets of genes in different strains of vaccinia virus. | ||||||
Koonin et al. Biology Direct 2006 1:29 doi:10.1186/1745-6150-1-29 |
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