Influenza viruses are characterized by segmented genomes allowing reassortment. Which statement best describes this feature?

• A. Non-segmented genome
• B. Monopartite RNA genome
• C. Segmented genome allowing reassortment
• D. Double-stranded DNA genome

Answer: (C)

A key idea here is that influenza has a segmented genome, which lets different genome pieces mix and match when two viruses infect the same cell. Because the eight RNA segments can assort independently, progeny can inherit a new combination of segments from the parent strains. This reassortment can produce major changes in surface proteins, like hemagglutinin and neuraminidase, leading to what scientists call an antigenic shift. That rapid genetic reshuffling is possible specifically because the genome is segmented. If the genome were non-segmented, or monopartite, such mixing wouldn’t happen, and changes would come only from slower point mutations. A double-stranded DNA genome would describe a different type of virus altogether, which isn’t the case for influenza.