Figure 2. Distribution of adjusted palindrome index (API) scores.
Scores over all 4,521 HTLV-1 integration site sequences (top, taking the sequence length to be 2n = 26, where n is the number of positions each side of the line of palindromic symmetry) and over all 13,442 HIV-1 integration sequences (bottom, with 2n +1 = 25). In both cases, the API for the corresponding consensus sequence (indicated by the red dashed line) is in the extreme positive tail of the distribution.