Although nucleotide sequences of different isolates of rice dwarf phyt
oreovirus are highly conserved genome variants can be identified from
mobility differences detected in polyacrylamide electrophoresis gels.
These differences may be due to base substitutions, deletions, or rear
rangements of the dsRNAs. Using known variants, segment reassortment h
as been experimentally demonstrated for the first time with plant reov
iruses, although with some other members of the Reoviridae, it is well
documented. The technique for making genetic resassortants could be u
sed to identify genes involved in certain characters such as insect tr
ansmissibility, types of symptom expression, and host specificity.