In ascoviruses, the genome consists of a single circular DNA molecule ranging from 119-to 180-kpb in size [7] . Phylogenetic analyses of several viral genes have revealed that ascoviruses are closely related to iridoviruses [22] , and likely evolved from them. In contrast, the genome of ichnoviruses is composed of multiple circular DNA molecules (25 to 105) representing a total size of 250 to 300kbp, all of which are replicated from the wasp chromosomes. The ichnovirus proviral genome is specifically excised and amplified in several segments in the female calyx cells, the only wasp tissue in which ichnovirus virogenesis occurs. After assembly, these particles are secreted into the female genital tract. Once injected into the host, the ichnovirus genome does not replicate, and does not lead to the production of a new virus generation. The third characteristic of ichnoviruses is that most of the genes borne by the particles are not related to viral genes. Among the 7 annotated ichnovirus gene families, there are four (rep, PRRP, N, and TrV) for which no homology with known eukaryotic (or prokaryotic) proteins has been detected and for which no function has been proposed. Among the remaining three (cys, ank and inx), cys-motif proteins have no clear homologs among eukaryotic (or prokaryotic) proteins, although the "cysteine knot" that they form is a folding domain found in many proteins, but not one that is necessarily related to eukaryotic host immune systems [10, 14] . However, some protein domains and their putative functions suggest that they might be related to regulatory components of eukaryotic host defence systems that are not sufficiently elucidated.