With the caveat that I have only had this explained to me ... The one location in the HIV genome that consistently doesn't mutate is the hexamer boundary of th

With the caveat that I have only had this explained to me ... The one location in the HIV genome that consistently doesn't mutate is the hexamer boundary of the viral capsid. Seems like that would make a better taerget sequence as a result. Anyone here know why they chose the sequences that they did?