Evidence for a chromosomal location of polydnavirus DNA in the ichneumonid parasitoid Hyposoter fugitivus

Abstract

Evidence is presented in support of a chromosomal location for sequences homologous to polydnavirus DNA in the ichneumonid parasitoid Hyposoter fugitivus. In this study, four different viral genome segments were cloned and used as probes against genomic DNA extracted from male parasitoids and digested with a variety of restriction enzymes. Each probe typically identified a single off-size fragment (OSF) in the case of enzymes not cutting viral genome segments, while two OSFs were generated by enzymes cutting at one and two sites. While extra OSFs were occasionally observed, these were invariably found to be due to the presence of polymorphic restriction sites in flanking chromosomal DNA. Analysis of these data suggests that a single, stable chromosomal locus exists for sequences homologous to each viral genome segment; the data also indicate that viral and cognate parasitoid genomic DNAs are largely if not entirely colinear.