scientists have grouped the isolates into three different groups. within each group, the genomes share 91.0-99.8% of the same sequence identity, and the three groups share 78.0-89.3% of the same sequence identity between each other. group iii is the most different from the other groups and only shares 78.0-79.6% sequence identity with the other groups. the symptom of gva that was the most different in each group was the vein clearing (when the plant loses the color in its veins). the grapevines infected with the group i strain of gva only show mild signs of vein clearing while the other groups show more intense signs of this. each group varies in the intensity of vein clearing present.