Virus classification is the process of naming viruses and placing them in a "family tree" associated with other viruses. This process is different from the process used to classify plants or animals. Due to fossil records, there is a clear link between most animals or plants. Viruses don't leave such records, so it's more difficult to determine the relationship between them. Another factor contributing to the difficulty of virus classification is their pseudo-life nature. Many scientists are arguing whether viruses should be considered alive because they lack some standards that are considered important to living things. This makes it difficult for viruses to be placed in current plant and animal classification systems.
The virus classification is currently based on five phenotypic characteristics; the morphology or structure of the virus; the nucleic acid type or genetic material of the virus; the mode of replication; the host; and the type of disease they cause. There are currently two classification systems, the Baltimore System and the International Classification Committee for Virus Classification.
The Baltimore classification system was developed by Nobel Prize-winning biologist David Baltimore. The system divides the virus into seven groups based on the type of genetic material, the number of strands of the genetic material, and their method of replication, expressed in Roman numerals. There are other classification systems based on the morphology of the virus or the disease caused. Since some diseases are caused by different viruses, these systems are inadequate, and the common cold or flu is the most common example, and some viruses look very similar to each other. Another factor is that the viral structures are difficult to determine under the microscope because they are small. By classifying viruses based on their genetic material, some indications of how to conduct the study are provided, as the viruses in the class behave in a similar manner.
The seven groups are: the first group, double-stranded DNA viruses such as herpes virus and varicella virus; Group II, single-stranded DNA viruses such as parvo virus; Group III, double-stranded RNA virus; Group IV, sense single-stranded RNA virus Such as Sars virus, yellow fever virus and many other well-known viruses; Group V, negative sense single-stranded RNA viruses such as measles virus, mumps virus and rabies virus; Group VI, reverse transcription RNA and other HIV viruses; Group VII, a retroviral DNA virus, such as hepatitis B virus. Group VI viruses use this enzyme to reverse-transcribe their RNA into DNA, and then insert the transcribed DNA into the DNA of the host organism, which is replicated whenever the cell divides. The Group VII virus transcribes its DNA into an RNA form, and then transcribes the RNA back into the DNA to insert into the host's DNA and replicate.
In the early 1990s, the International Classification of Viruses developed and implemented virus naming and classification rules. The team still monitors today's virus classification. The ICTV system shares many features with the system used to classify cellular organisms. But there are a few differences; the classification of cell biology begins in the kingdom, while the virus begins in order; the other difference is that species names generally take the form of disease types. For example, the classification of yellow fever virus is; family - flavivirus, genus - flavivirus, species - yellow fever virus. Please note that this virus does not have an order classification; this is because the recognition of the order is very slow and only three orders have been named for more than ten years. Many of the 80 known families are still not placed. ICTV is still studying this aspect of virus classification.
Orignal From: Virus classification
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