Divided genomes and intrinsic noise

Area of Science:

• Virology
• Molecular Biology
• Evolutionary Biology

Background:

• Segmental genomes are common in RNA viruses but rare in DNA viruses.
• Previous hypotheses suggest RNA virus segmentation increases variation through reassortment.
• This relies on the limited recombination capabilities of RNA molecules compared to DNA.

Purpose of the Study:

• To propose a novel hypothesis for the evolutionary advantage of genome segmentation in RNA viruses.
• To explain why segmentation is prevalent in RNA viruses and absent in DNA viruses.

Main Methods:

• Comparative analysis of RNA and DNA virus replication error rates.
• Theoretical modeling of genome segmentation under varying mutation and recombination rates.
• Evaluation of selective pressures favoring modular RNA genomes.

Main Results:

• RNA genomes exhibit significantly higher error rates (10^-3 to 10^-4) than DNA genomes (10^-9 to 10^-11).
• Genome segmentation increases the probability of information survival through a high-noise replication process.
• Segmentation is advantageous for modular RNAs, especially when packaged separately, as seen in reoviruses.

Conclusions:

• High mutation rates in RNA replication favor genome segmentation for enhanced survival.
• Segmentation acts as a protective mechanism, increasing the fidelity of genetic information transmission.
• The selective advantage of segmentation is linked to the error-proneness of RNA polymerases and packaging strategies.