The DNA content of four small iridescent viruses: genome size, redundancy, and homology determined by renaturation kinetics

Fragmented DNA preparations from iridescent virus types 2, 6, 9, and 18 have been characterised for GC content and fragment size as a prelude to hybridisation studies. The genome size of the DNAs have been found to be 147 × 10⁶, 152 × 10⁶, 114 × 10⁶, and 114 × 10⁶ daltons for iridescent virus types 2, 6, 9, and 18, respectively, by studies of the kinetics of renaturation. Iridescent virus types 2 and 6 were found to contain a small proportion of DNA reannealing more rapidly than the bulk of the DNA, indicative of the presence of repeated sequences. In addition, the nucleotide sequence homology among the viruses has been investigated and found to range from 0 to 100%.