( ( ( Targeted gene ) ( walking ( polymerase ( chain reaction ) ) ) ) . )
(ROOT (NP (NP (JJ Targeted) (NN gene)) (VP (VBG walking) (NP (NN polymerase) (NN chain) (NN reaction))) (. .)))
Targeted gene walking polymerase chain reaction.
(ROOT (S (NP (DT The) (NN polymerase) (NN chain) (NN reaction)) (VP (VBZ is) (NP (NP (DT a) (NN way)) (PP (IN of) (S (VP (VBG making) (NP (NP (NNS copies)) (PP (IN of) (NP (DT a) (NN gene))))))))) (. .)))