Classification of Viruses is to name and place the virus into different groups or subgroups in phylum Vira. The viruses are placed or classified into a group or sub-phylum on the basis of their different characteristics (Phenotypic Characteristics). Those characteristics are as follow:
Phenotypic Characters of Viruses
1. Type of nucleic acid (DNA or RNA) they have.
2. Morphology of Virus (Form and Structure of Virus)
3. Type of disease they cause in their host.
4. Mode of Replication
5. Type of host in which they live.
6. The Host is either animal or a plant.
But let just define what virus is and what is its origin?
The non-cellular infectious entities which contain RNA or DNA encased in protein coat and reproduce only in living cell is called virus. The word “Virus” is derived from Latin word “Venom”, which means poisonous substance and was used to describe any disease-causing substance.
Classification of Viruses
Classification of viruses is as follow:
All viruses are belonged to this phylum. It has two sub-phyla:
The sub-phylum includes viruses with DNA core. It has three classes.
(i) Class Deoxyhelica: This class includes DNA viruses. They have helical symmetry. This class has only one order: Chaetovirales. It has a single family: Poxviridae.
(ii) Class Deoxycubica: This class contains DNA viruses. But they have cubical symmetry. It has two orders:
- Haplovirales: They are without envelope. It has six families.
- Peplovirles: They have envelope. It has only one family: Herpesvirdae.
(iii) Class Deoxybinala: The class possesses DNA containing binal viruses. They have single order Urovirates. It has only one family Phagoviriclae.
These viruses contain RNA core. It is further divided into two classes.
(i) Class Ribohelica: It includes RNA viruses. They have helical symmetry. The class includes two orders:
- Rhabdovirales: They are without envelopes. It has six families.
- Sagorvirales: They have envelope. It has three families.
(ii) Class: Ribocubica: The class contains RNA viruses. They have cubical symmetry. It consists of two orders:
- Gymnovirales: They are without envelope. It has two families.
- Togovirales: They have envelopes. It consists of single family.