Reassortment

Reassortment is a natural phenomenon that occurs in viral genetics when viruses with segmented genomes (multiple pieces of RNA or DNA) exchange genetic material. This process is most commonly associated with influenza viruses, particularly those of the Orthomyxoviridae family.

Mechanism

Reassortment occurs when two or more different strains of a virus, or strains of different viruses, infect the same cell in a host. This can lead to a shuffling of the genetic material from the different strains, resulting in a new subtype. This process is distinct from recombination, which involves the breaking and rejoining of single strands of genetic material.

Role in Influenza

In the case of influenza viruses, reassortment can lead to the emergence of new strains that can cause pandemics. This is because the new subtype may have different antigenic properties than the original strains, allowing it to evade the immune response of individuals who have immunity to the original strains. This was the case in the 1957 and 1968 influenza pandemics, which were caused by reassortant viruses.

Role in Other Viruses

While reassortment is most commonly associated with influenza viruses, it can also occur in other segmented viruses, such as the rotaviruses, Bunyavirales, and Reoviridae. In these viruses, reassortment can also lead to the emergence of new strains with different antigenic properties.

See Also

• Antigenic shift
• Genetic recombination
• Viral evolution

References

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  Reassortment