Fig. 3.

Key characteristics of BVs as understood in 2013. Sequence data established that BV proviral segment loci are organized into multiple loci, which are amplified without excision in calyx cells. Multiple nudivirus-like core genes had also been identified and shown to be required for virion formation. Proviral segment loci and nudivirus-like genes were hypothesized to reside in close physical proximity to one another in the genomes of wasps although precise locations remained unknown (hash marks). Experiments also established that circularized DNAs in BV virions integrate into the genome of infected host cells.