Initially after viruses were discovered there was no system for classifying viruses. Consequently viruses were named haphazardly. Most of the vertebrate viruses have been named according to:
the associated diseases (poliovirus, rabies)
the type of disease caused (murine leukemia virus),
the sites in the body affected or from which the virus was first isolated (rhinovirus, adenovirus)
the places from where they were first isolated (Sendai virus, Coxsackievirus)
the scientists who discovered them (Epstein-Barr virus), or
due to common cultural perceptions e.g. influenza ‘influence’ of bad air or dengue ‘evil spirit’
Characteristics used to classify viruses
According to the classification, viruses are grouped according to their properties, not the cells they infect. The main criteria were the type of nucleic acid – DNA or RNA.
Four characteristics were to be used for the classification of all viruses:
Type of the nucleic acid including size of the genome, strandedness (single or double), linear or circular, positive or negative (sense), segments (number and size), sequence and G+C content etc.
Symmetry of the protein shell
Presence or absence of a lipid membrane
Dimensions or the size of the virion and capsid
Other properties include the physicochemical properties including molecular mass, pH, thermal stability, susceptibility to chemicals and physical extremes and to ether and detergents.
Other characteristics which were subsequently added include the type of disease caused, and which animals and tissues are infected. With the development of nucleic acid sequencing technologies in the 1970s, genomics has played an increasingly important role in taxonomy. Today new viruses are assigned to families based on the nucleic acid sequence of their genome.
Four characteristics were to be used for the classification of all viruses:
Type of the nucleic acid including size of the genome, strandedness (single or double), linear or circular, positive or negative (sense), segments (number and size), sequence and G+C content etc.
Symmetry of the protein shell
Presence or absence of a lipid membrane
Dimensions or the size of the virion and capsid
Other properties include the physicochemical properties including molecular mass, pH, thermal stability, susceptibility to chemicals and physical extremes and to ether and detergents.
Other characteristics which were subsequently added include the type of disease caused, and which animals and tissues are infected. With the development of nucleic acid sequencing technologies in the 1970s, genomics has played an increasingly important role in taxonomy. Today new viruses are assigned to families based on the nucleic acid sequence of their genome.
the ictv classification
Naming convention primarily depends on the genome and nucleic acid material of the viruses with the development of nucleic acid sequencing technologies in the 1970s. Naming is performed by the International Committee on the Taxonomy of Viruses (ICTV). A complete catalog of known viruses is maintained by the ICTV at ICTVdb.
The order is as follows;
Order – virales
Family –viridae
Subfamily –virinae
Genus –virus
Species –virus
In the 2011 ICTV classification there are six orders – Caudovirales, Herpoesvirales, Mononegavirales, Nidovirales, Picornavirales and Tymovirales. The seventh Ligamenvirales has been proposed.
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The order is as follows;
Order – virales
Family –viridae
Subfamily –virinae
Genus –virus
Species –virus
In the 2011 ICTV classification there are six orders – Caudovirales, Herpoesvirales, Mononegavirales, Nidovirales, Picornavirales and Tymovirales. The seventh Ligamenvirales has been proposed.
i love u p umma
The Baltimore classification
The Baltimore classification is based on genetic contents and replication strategies of viruses. The genetic material in all types of cells is double-stranded DNA, but some viruses use RNA or single-stranded DNA to carry genetic information.
According to Baltimore classification, viruses are divided into the following seven classes:
dsDNA viruses
ssDNA viruses
dsRNA viruses
(+)-sense ssRNA viruses
(-)-sense ssRNA viruses
RNA reverse transcribing viruses
DNA reverse transcribing viruses
where "ds" represents "double strand" and "ss" denotes "single strand".
Table->>> Examples of common viruses.
ss = single strand; ds = double strand.
(+) RNA is the one which can function as mRNA for the synthesis of proteins. (-) RNA cannot function as mRNA.
Reovirus and influenza virus have segmented RNA genomes; the total length is shown here.
According to Baltimore classification, viruses are divided into the following seven classes:
dsDNA viruses
ssDNA viruses
dsRNA viruses
(+)-sense ssRNA viruses
(-)-sense ssRNA viruses
RNA reverse transcribing viruses
DNA reverse transcribing viruses
where "ds" represents "double strand" and "ss" denotes "single strand".
Table->>> Examples of common viruses.
ss = single strand; ds = double strand.
(+) RNA is the one which can function as mRNA for the synthesis of proteins. (-) RNA cannot function as mRNA.
Reovirus and influenza virus have segmented RNA genomes; the total length is shown here.
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