Navigation Links
Virus classification


Viruses can be classified in several ways, such as by their geometry, by whether they have envelopes, by the identity of the host organism they can infect, by mode of transmission, or by the type of disease they cause. The most useful classification is probably by the type of nucleic acid the virus contains and its mode of expression. This classification was proposed by Nobel-prize winner David Baltimore. It should be noted that none of these classifications are expected to be phylogenetic, as viruses may not share a common origin.

Contents
1 Overview
2 Classification by genome type

2.1 DNA viruses

2.1.1 Group I - dsDNA viruses (double stranded DNA)
2.1.2 Group II - ssDNA viruses (single stranded DNA)

2.2 RNA viruses

2.2.1 Group III - dsRNA viruses (double stranded RNA)
2.2.2 Group IV - (+)ssRNA viruses (positive single stranded RNA or mRNA like)
2.2.3 Group V - (-)ssRNA viruses (negative single-stranded RNA)

2.3 DNA and RNA Reverse Transcribing viruses

2.3.1 Group VI - ssRNA-RT viruses (single stranded RNA)
2.3.2 Group VII - dsDNA-RT viruses (double stranded DNA)

3 Subviral agents

3.1 Viroids
3.2 Satellites
3.3 Prions

4 Other resources

4.1 External links
4.2 See also

Overview

The various forms of viruses arise because one of the two strands of DNA in which all cellular life forms store their genetic information is redundant, so that viruses can have either single-stranded or double-stranded genomes. Furthermore, some viruses store their genome in RNA rather than in DNA form. RNA arises in cells as an intermediate when genes are translated into proteins. RNA genomes of viruses can be encoded in two different directions: Either the genes are stored in the 5'->3' direction (positive or + polarity), analogous to the direction in which genes are represented in mRNA in cells, or the genes are stored in the opposite direction (negative or - polarity).

The taxonomy of viruses is similar to that of cellular organisms:

Order (-virales)
Family (-viridae)
Subfamily (-virinae)
Genus (-virus)
Species

However, the code of nomenclature regulated by the International Committee on Taxonomy of Viruses differs from the others on several points. Most notably, names of orders and families are italicized, and species names are not binomial - instead, they generally take the form of [Disease] Virus. The recognition of orders is very recent and has been deliberately slow; to date, only three have been named, and most families remain unplaced. Approximately 80 families and 4000 species of virus are known.

Classification by genome type

DNA viruses

Group I - dsDNA viruses (double stranded DNA)

Group II - ssDNA viruses (single stranded DNA)

RNA viruses

Group III - dsRNA viruses (double stranded RNA)

Group IV - (+)ssRNA viruses (positive single stranded RNA or mRNA like)

Group V - (-)ssRNA viruses (negative single-stranded RNA)

DNA and RNA Reverse Transcribing viruses

Group VI - ssRNA-RT viruses (single stranded RNA)

Group VII - dsDNA-RT viruses (double stranded DNA)

Subviral agents

The following agents are smaller than viruses but have some of their properties.

Viroids

  • Family Pospiviroidae
    • Genus Pospiviroid; type species: Potato spindle tuber viroid
    • Genus Hostuviroid ; type species: Hop stunt viroid
    • Genus Cocadviroid ; type species: Coconut cadang-cadang viroid
    • Genus Apscaviroid ; type species: Apple scar skin viroid
    • Genus Coleviroid ; type species: Coleus blumei viroid 1
  • Family Avsunviroidae
    • Genus Avsunviroid ; type species: Avocado sunblotch viroid
    • Genus Pelamoviroid ; type species: Peach latent mosaic viroid

Satellites

  • Satellite viruses
    • Single-stranded RNA satellite viruses
      • Sugroup 1: Chronic bee-paralysis satellite virus
      • Subgroup 2: Tobacco necrosis satellite virus
  • Satellite nucleic acids
    • Single-stranded satellite DNAs
    • Double-stranded satellite RNAs
    • Single-stranded satellite RNAs
      • Subgroup 1: Large satellite RNAs
      • Subgroup 2: Small linear satellite RNAs
      • Subgroup 3: Circular satellite RNAs

Prions

  • Fungal prions
  • Mamalian prions

Other resources

External links

See also


'"/>


Other biology definition
(Date:8/20/2008)...al Human Genome Research Institute (NHGRI), part o...warded more than $20 million in grants to develop ... efficient enough to sequence a person,s DNA as a ...e. , "The ability to comprehensively sequence a...ded to usher in an age of personalized medicine wh...
(Date:8/19/2008)...up of University of Oklahoma researchers began stu... problem that has plagued the energy industry for ... a community of microorganisms capable of converti...hers found that the groundbreaking processknown as...imulate methane gas production from older, more ma...
(Date:8/19/2008)...on that often goes undetected can block the lung,s..., according to researchers at National Jewish Heal...heduled to appear in the October issue of Infecti...ause smokers to develop chronic obstructive pulmon...ming cause of chronic obstructive pulmonary diseas...
(Date:8/19/2008)...I, AUGUST 18, 2008 With oil prices skyrocketing, ...fuels. Research published this month in Agronomy ... stover. , Corn stover is made up of the leaves...eld after harvesting the edible corn grain. Corn s...rop needed by 2030. , Scientists with the USDA-...
Breaking Biology News(10 mins):NHGRI seeks DNA sequencing technologies fit for routine laboratory and medical use 2NHGRI seeks DNA sequencing technologies fit for routine laboratory and medical use 3NHGRI seeks DNA sequencing technologies fit for routine laboratory and medical use 4NHGRI seeks DNA sequencing technologies fit for routine laboratory and medical use 5OU researchers isolate microorganisms that convert hydrocarbons to natural gas 2OU researchers isolate microorganisms that convert hydrocarbons to natural gas 3Infection blocks lung's protective response against tobacco smoke 2Hodgkin Lymphoma Kids Face Greater Risk of Future Problems 20754 1Hodgkin Lymphoma Kids Face Greater Risk of Future Problems 20754 2Phase III Study of Abbotts Investigational TriLipix 28TM 29 in Combination With AstraZenecas CRESTOR 28R 29 Meets Primary Endpoints on Key Lipids 2257 1Phase III Study of Abbotts Investigational TriLipix 28TM 29 in Combination With AstraZenecas CRESTOR 28R 29 Meets Primary Endpoints on Key Lipids 2257 2Phase III Study of Abbotts Investigational TriLipix 28TM 29 in Combination With AstraZenecas CRESTOR 28R 29 Meets Primary Endpoints on Key Lipids 2257 3Phase III Study of Abbotts Investigational TriLipix 28TM 29 in Combination With AstraZenecas CRESTOR 28R 29 Meets Primary Endpoints on Key Lipids 2257 4Study Confirms That Avastin Significantly Increases Chance of Living Without Disease Progression in Metastatic Breast Cancer 2255 1Study Confirms That Avastin Significantly Increases Chance of Living Without Disease Progression in Metastatic Breast Cancer 2255 2Study Confirms That Avastin Significantly Increases Chance of Living Without Disease Progression in Metastatic Breast Cancer 2255 3Poniard Announces Positive First Line Efficacy and Safety Data From Ongoing Phase 2 Trial of Picoplatin in Patients with Metastatic Hormone Refractory 2252 1Poniard Announces Positive First Line Efficacy and Safety Data From Ongoing Phase 2 Trial of Picoplatin in Patients with Metastatic Hormone Refractory 2252 2Poniard Announces Positive First Line Efficacy and Safety Data From Ongoing Phase 2 Trial of Picoplatin in Patients with Metastatic Hormone Refractory 2252 3Poniard Announces Positive First Line Efficacy and Safety Data From Ongoing Phase 2 Trial of Picoplatin in Patients with Metastatic Hormone Refractory 2252 4
...sh waters occurs worldwide but is largely unrecogn...ressures can obscure fishery declines, according t...nce. , Although the status of inland waters and th...ts to freshwater fisheries and associated biodiver...on groups and the media, according to author J. Da...
...gists at the Department of Energy,s Lawrence Berke...at can select tens of thousands of high-quality im...phs, rapidly and automatically, with accuracy appr... new algorithm, described as "particle picking by ...eed and power of methods for determining biologica...
...science proves it. A man,s brain and a woman,s bra...m the University of Alberta shows that men and wom...hey perform the same tasks. The results of the res...Image. , The study involved volunteers who perfor...ks and simple motor tasks while their brain activi...
...detailed Dec. 4 as an advance online publication o...ith autism have virtually no activity in a key par...ing and observing emotions. , Mirror neurons fire ...while he or she observes the same action performed...on-execution matching system provides a neural mec...
Other Biology News:Overfishing in inland waters reduces biodiversity and threatens health 2Picking particles faster than one at a time 2Picking particles faster than one at a time 3Picking particles faster than one at a time 4Picking particles faster than one at a time 5Men and women differ in brain use during same tasks 2UCLA imaging study of children with autism finds broken mirror neuron system 2