{HEAD ~ A method} of screening for {TAIL ~ a nucleoside analog} that is incorporated and extended at high efficiency by reverse transcriptase of human immunodeficiency virus and causes incorrect base pairing, said analog incorporated preferentially by HIV RT relative to incorporation by a mammalian DNA polymerase, comprising: 
{ HEAD ~ A method } of screening for { TAIL ~ a nucleoside analog } that is incorporated and extended at high efficiency by reverse transcriptase of human immunodeficiency virus and causes incorrect base pairing , said analog incorporated preferentially by HIV RT relative to incorporation by a mammalian DNA polymerase , comprising :
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH