GENETIC RELATEDNESS AMONG DSRNAS FROM DIFFERENT ISOLATES OF DISCULA-DESTRUCTIVA

The genetic relationships among double-stranded RNAs (dsRNAs) from 76 isolates of Discula destructiva obtained from different geographic loc ations from New York to Alabama were studied by dot-blot hybridization . The dsRNA segments, identified by agarose gel electrophoresis, varie d in size and number. Probes were constructed from total dsRNA from si x isolates with different dsRNA profiles and of different geographic o rigins. Each probe hybridized with dsRNA from ca. 62% of the isolates under the high-stringency washing conditions used. No major difference s in the percentage of the total isolates that hybridized with each pr obe were observed. These results suggest a recent common origin of the se isolates of D. destructiva.