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