Occurrence of the reverse sequences around the top 50 forward and reverse HFSs. The frequencies of the reverse sequences starting from a particular position around the first base of the HFSs were calculated. The frequency profile of the forward and reverse HFSs are near identical, with position +2 reverse sequences (R+2) having a remarkablely higher occurrence than the others.
Jiang et al. Virology Journal 2011 8:194 doi:10.1186/1743-422X-8-194