View Program - 63rd Annual Drosophila Research Conference

Galbut virus is a double-stranded RNA virus in the family Partitiviridae that is found in 100% of D. melanogaster populations but only in ~60% of individuals within those populations. Galbut virus infection produces no obvious phenotype, however, a small fitness cost could be sufficient to select for resistance, and multiple lines of evidence support the hypothesis that some flies are resistant to infection. Endogenous viral elements (EVE) are integrated viral sequences that represent potential mechanisms of viral resistance. Recently, a galbut virus EVE has been identified in European D. melanogaster populations. I hypothesized that the galbut virus EVE might confer resistance to galbut virus infection. To test this hypothesis, I created a line of flies homozygous for the EVE by crossing an inbred line containing the EVE, (Global Diversity Line N14) and a robust inbred line from the Drosophila Genetic Reference Panel (DGRP strain 517). To test whether flies with the EVE can become infected, I microinjected galbut virus EVE+ individuals and found that only a small frequency (less than 1%) of offspring of injected parents were infected. To test whether the EVE is responsible for resistance, I am using CRISPR/Cas9 to remove the EVE. By removing the EVE, experiments can be done in parallel with EVE+ and non-EVE flies that are identical otherwise to test whether the EVE is actually conferring resistance.

Drosophila melanogaster containing a galbut virus endogenous viral element are resistant to infection