Mutations in genetic information are random. It's not that the virus WANTED the change, it randomly occurred. Who would have explain that the coronavirus wanted to change and that's why it was able to survive?
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Answer:
Explanation:
The mutation rates of DNA viruses approximate those of eukaryotic cells, yielding in theory one mutant virus in several hundred to many thousand genome copies. RNA viruses have much higher mutation rates, perhaps one mutation per virus genome copy. Mutations can be deleterious, neutral, or occasionally favorable. Only mutations that do not interfere with essential virus functions can persist in a virus population.
Phenotypic Variation by Mutations
Mutations can produce viruses with new antigenic determinants. The appearance of an antigenically novel virus through mutation is called antigenic drift. Antigenically altered viruses may be able to cause disease in previously resistant or immune hosts.
Vaccine Strains from Mutations
Mutations can produce viruses with a reduced pathogenicity, altered host range, or altered target cell specificity but with intact antigenicity. Such viruses can sometimes be used as vaccine strains.
Recombination
Recombination involves the exchange of genetic material between two related viruses during coinfection of a host cell.
Recombination by Independent Assortment
Recombination by independent assortment can occur among viruses with segmented genomes. Genes that reside on different pieces of nucleic acid are randomly assorted. This can result in the generation of viruses with new antigenic determinants and new host ranges. Development of viruses with new antigenic determinants through independent assortment is called antigenic shift.
Recombination of Incompletely Linked Genes
Genes that reside on the same piece of nucleic acid may undergo recombination. The closer two genes are together, the rarer is recombination between them (partial linkage).
Phenotypic Variation from Recombination
Development of viruses with new antigenic determinants by either type of recombination may allow viruses to infect and cause disease in previously immune hosts.
Vaccines through Recombination
Vaccine strains of viruses can be used to create recombinant viruses that carry extra genes coding for a specific immunogen. During viral vaccination, the replicating virus will express the specific immunogen. Specific antibody production will be stimulated, and the host will be protected from the immunogen as well as from the vaccine virus.
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Introduction
Viruses are simple entities, lacking an energy-generating system and having very limited biosynthetic capabilities. The smallest viruses have only a few genes; the largest viruses have as many as 200. Genetically, however, viruses have many features in common with cells. Viruses are subject to mutations, the genomes of different viruses can recombine to form novel progeny, the expression of the viral genome can be regulated, and viral gene products can interact. By studying viruses, we can learn more about the mechanisms by which viruses and their host cells function.
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Genetic Change in Viruses
This chapter covers the mechanisms by which genetic changes occur in viruses. Two principal mechanisms are involved: mutation and recombination. Alterations in the genetic material of a virus may lead to changes in the function of viral proteins. Such changes may result in the creation of new viral serotypes or viruses of altered virulence.
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Mutations
Mutations arise by one of three mechanisms: (1) by the effects of physical mutagens (UV light, x-rays) on nucleic acids; (2) by the natural behavior of the bases that make up nucleic acids (resonance from keto to enol and from amino to imino forms), and (3) through the fallibility of the enzymes that replicate the nucleic acids. The first two mechanisms act similarly in all viruses; hence, the effects of physical mutagens and the natural behavior of nucleotides are relatively constant. However, viruses differ markedly in their mutation rates, which is due primarily to differences in the fidelity with which their enzymes replicate their nucleic acids. Viruses with high-fidelity transcriptases have relatively low mutation rates and vice versa.
Answer:
CORONA VIRUS DONOT WANT CHANGE ANY GENETIC TRACT BUT IT REDUCES IMMUNE SYSTEM AND LET ITSELF AND OTHER CONGESTIVE TO ATTACK ON OUR BODY