We recently sequenced the DpAV4 genome, and a combination of our analysis of this genome and recent data from new types of ichnoviruses, as well as new software programs that elucidate protein relationships based on structural analysis, have enabled us to detect phylogenetic relationships between proteins encoded by open reading frames of DpAV4 and the Glypta fumiferanae (GfIV) and Campolitis sonorensis (CsIV) ichnoviruses. In support of the symbiogenesis hypothesis for the origin of ichnoviruses, data and analyses suggest two independent symbiogenic events, in agreement with what was previously proposed [28] . The first led to the ichnoviruses in Banchinae lineage. This hypothesis is based on the occurrence of a gene cluster present in GfIV and DpAV4. The second symbiogenic event led to ichnoviruses in the Campopleginae wasp lineage. This hypothesis is based on relationships of the major capsid proteins among CsIV, ascoviruses and iridoviruses. Extending our investigations to proteins encoded by open reading frames of certain ascoviruses and bracoviruses, hosts and bacteria, in the light of recent analyses about the involvement of the replication machinery of virus groups related to ascoviruses in lateral gene transfer [29] , we discuss the robustness and the limits of the molecular evidence supporting an ascovirus origin for ichnovirus lineages.