Author: Seohyung Jeong
Editor: Jiho Chang
Variation in Virus
Natural selection can only happen when it has the right starting material: genetic variation. Genetic variation means that there are some genetic (heritable) differences in a population. Virus mutation creates a number of genetic variations, which can lead to opposing actions of selection, unpredictable new mutation (you will need to add extra explanation about these ‘opposing actions’) and random genetic drift to affect by (how?) the population of the viruses. When the population is large, the virus has more opportunity to adapt to that new environment, but when the population is small, the random mutation will take less place to adapt and make some other random change.
Recombination: viruses swap chunks of genetic material (DNA or RNA).
Random mutation: a change occurs in the DNA or RNA sequence of a virus.
Recombination
. Recombination usually happens when two viruses are infected in the same cell.
Similar regions of viral genomes can exchange pieces
Influenza viruses have eight RNA segments, each carrying one or a few genes.
Why do viruses evolve so fast
Mutation rate helps them evolve quickly by providing more variation from the starting virus. When the mutation causes the virus to increase with a large population size and rapid lifecycle, it leads to a higher number of viruses with particular random mutation. Because when the population of viruses increases, the mutation also increases so the viruses can reproduce quickly and evolve faster.
What is the Mutation rate
Mutation rate is typically defined as the average number of errors created in genomes of viral progeny, per base, per replication cycle (mut/nuc/rep).
Khan Academy. (n.d.). Evolution of viruses (article). Khan Academy. Retrieved April 23, 2022, from https://www.khanacademy.org/science/ap-biology/natural-selection/common-ancestry-and-continuing-evolution/a/evolution-of-viruses
Stern, A., & Andino, R. (2016, February 12). Viral evolution: It is all about mutations. Viral Pathogenesis (Third Edition). Retrieved April 23, 2022, from https://www.sciencedirect.com/science/article/pii/B9780128009642000173
Domingo, E. (2020). Molecular basis of genetic variation of viruses: Error-prone replication. Virus as Populations. Retrieved April 23, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153327/#:~:text=Viruses%20use%20the%20same%20molecular,recombination%2C%20and%20genome%20segment%20reassortment
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