Repeatable Population Dynamics among Vesicular Stomatitis Virus Lineages Evolved under High Co-infection

Area of Science:

• Virology
• Evolutionary Biology
• Ecology

Background:

• Species interactions, like parasites and hosts or viruses, can lead to cyclical population dynamics.
• Defective-interfering particles (DIPs) are viral variants that can impact the replication of standard viruses during co-infection.

Purpose of the Study:

• To investigate the repeatability of oscillatory dynamics and molecular evolution in vesicular stomatitis virus (VSV) populations under frequent co-infection.
• To determine if independently evolved VSV populations exhibit similar cyclical dynamics and genetic changes.

Main Methods:

• Passaging VSV populations under conditions promoting frequent cellular co-infection.
• Monitoring viral population densities over experimental passages.
• Genomic analysis to identify molecular substitutions and mutations.

Main Results:

• VSV populations exhibited identical cyclical dynamics in early passages, transitioning to repeatable dampened oscillations by passage 20.
• Parallel molecular substitutions, including dominant novel mutations, were observed across independently evolved populations.
• Frequent co-infection with DIPs significantly reduced the population densities of full-length VSV compared to clonal infections.

Conclusions:

• Oscillatory dynamics and molecular evolution of interacting viruses are highly repeatable under frequent co-infection.
• DIPs play a significant role in shaping viral population dynamics and evolution, leading to reduced performance of standard viruses.