Recurrent evolution of high virulence in isolated populations of a DNA virus

• Published in: eLife Vol. 9
• Main Authors: Hill, Tom, Unckless, Robert L
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 28.10.2020; eLife Sciences Publications, Ltd; eLife Sciences Publications Ltd
• Subjects: Analysis; Animal experimentation; Animals; Biological Evolution; co-evolution; DNA; DNA virus; DNA Virus Infections - veterinary; DNA Virus Infections - virology; DNA Viruses - genetics; DNA Viruses - isolation & purification; DNA Viruses - pathogenicity; DNA Viruses - physiology; Drosophila; Drosophila - virology; Drosophila innubila; Evolution (Biology); Evolutionary Biology; Female; Genetics and Genomics; Genomics; HIV; Humans; immunity; Insect viruses; Male; Virulence; Virulence (Microbiology); evolutionary biology; genetics; genomics; immunity; Drosophila innubila; DNA virus; co-evolution
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.58931

Hosts and viruses are constantly evolving in response to each other: as a host attempts to suppress a virus, the virus attempts to evade and suppress the host's immune system. Here, we describe the recurrent evolution of a virulent strain of a DNA virus, which infects multiple Drosophila species. Specifically, we identified two distinct viral types that differ 100-fold in viral titer in infected individuals, with similar differences observed in multiple species. Our analysis suggests that one of the viral types recurrently evolved at least four times in the past ~30,000 years, three times in Arizona and once in another geographically distinct species. This recurrent evolution may be facilitated by an effective mutation rate which increases as each prior mutation increases viral titer and effective population size. The higher titer viral type suppresses the host-immune system and an increased virulence compared to the low viral titer type.