FIG. 7.

Genome segment assignments and relative infectivities of ARV reassortants. Parental (black bars) and reassortant (gray bars) clones are identified at the extreme left. For each reassortant, the parental identity of each genome segment, as determined by its relative mobility by SDS-PAGE, is indicated (3 for ARV-138 and 7 for ARV-176). Reassortant virus stocks were standardized to give equal and countable numbers of focus-forming units in quail QM5 fibroblasts. The standardized inocula were then used to infect QM5 or HD-11 cell monolayers. The infected QM5 and HD-11 cell monolayers were fixed and immunostained, and the average number of foci per field was determined as described for Fig. 2. The relative infectivity was calculated as the ratio of HD-11/QM5 foci, and values were normalized to the relative infectivity of ARV-138 arbitrarily set to a value of 1. Results are presented as means and standard errors from three or more separate experiments.