FIG. 4.
NS2 viral mutants replace the wt in culture. The wt and the outlined NS2 mutants were inoculated onto 105 NB324K cells (MOI, 0.01) at PFU ratios of 9:1 and 1:1. Samples of total low-molecular-weight DNA were collected at 3 dpi (passage 1) or at 6 dpi (passage 2) from 105 cells inoculated with 1/10 of the virus harvested in the previous passage. Viral DNAs were amplified by PCR and then sequenced. Histograms show the sequence profiles of the viral genomes for the input virus used for initial infection and at each of the passages, with the consensus sequence shown above. The nucleotide position at which the competing genomes differ is underlined.