title: Repeatable Population Dynamics among Vesicular Stomatitis Virus Lineages Evolved under High Co-infection.
abstract: Parasites and hosts can experience oscillatory cycles, where the densities of these interacting species dynamically fluctuate through time. Viruses with different replication strategies can also interact to produce cyclical dynamics. Frequent cellular co-infection can select for defective-interfering particles (DIPs): "cheater" viruses with shortened genomes that interfere with intracellular replication of full-length (ordinary) viruses. DIPs are positively selected when rare because they out-replicate ordinary viruses during co-infection, but DIPs are negatively selected when common because ordinary viruses become unavailable for intracellular exploitation via cheating. Here, we tested whether oscillatory dynamics of ordinary viruses were similar across independently evolved populations of vesicular stomatitis virus (VSV). Results showed identical cyclical dynamics across populations in the first 10 experimental passages, which transitioned to repeatable dampened oscillations by passage 20. Genomic analyses revealed parallel molecular substitutions across populations, particularly novel mutations that became dominant by passage 10. Our study showed that oscillatory dynamics and molecular evolution of interacting viruses were highly repeatable in VSV populations passaged under frequent co-infection. Furthermore, our data suggested that frequent co-infection with DIPs caused lowered performance of full-length viruses, by reducing their population densities by orders of magnitude compared to reproduction of ordinary viruses during strictly clonal infections.
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven CT, USA.
authors.forename: Elizabeth S C P
authors.initials: ES
authors.lastname: Williams
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven CT, USA.
authors.forename: Nadya M
authors.initials: NM
authors.lastname: Morales
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven CT, USA.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Wasik
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA, USA.
authors.forename: Vesna
authors.initials: V
authors.lastname: Brusic
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA, USA.
authors.forename: Sean P J
authors.initials: SP
authors.lastname: Whelan
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven CT, USA.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Turner
keywords: RNA virus; cheating behavior; co-evolution; defective interfering particle; ecological dynamics; experimental evolution; virus ecology