highly significantP < 10 −5
Strikingly, we find that HIV-1 has a highly significant over-representation ( P < 10 −5 ) of well-cleaved sites separated with a distance of 13–19 nt, as compared to the cleavage distances we obtain when we repeatedly perform the same analysis on randomized versions of the HIV-1 sequence that preserve the local dinucleotide content (see ‘Materials and Methods’ section) (Figure 5C and Supplementary Figure S7a ).