Fig. 2

Skew analysis of HIV-1 RNA mutants with an altered A-bias. Skew analysis of the wt and mutant RNA genomes. Skew values (N1 − N2)/(N1 + N2) have been calculated in overlapping windows along the HIV-1 sequence from position 2212 to 3315, which represents the 498-nt Bcl1-Bst1107I fragment with 300-nt wt flanks. Window size was set at 10-nt with a step size of 2-nt, resulting in 550 data points on the X-axis. We used the same Y-axis for the cumulative skew values to allow a direct comparison of the compositional signatures of the wt and mutant RNA genomes