PNGS positions are aligned according to hxb2 aminoacid numeration. The aminoacid numeration is reported only for conserved PNGS. Squares point out the
increase of frequency of shifting PNGS.
      RS= Recent disease Stage; CS= Chronic disease Stage; LS= Late disease Stage.  | 
  
| Figure 4: Analysis of PNGSs pattern in V1, V2, V4 and V5 regions. |