( ( In 1953 ) ( , ( ( the ( two teams ) ) ( ( ( announced ( their discovery ) ) ( that ( DNA ( consists ( of ( ( two ( paired chains ) ) ( of ( units ( known ( as ( ( nucleotides , ) ( arranged ( in ( ( the shape ) ( of ( a helix ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (CD 1953))) (, ,) (NP (DT the) (CD two) (NNS teams)) (VP (VBD announced) (NP (PRP$ their) (NN discovery)) (SBAR (IN that) (S (NP (NNP DNA)) (VP (VBZ consists) (PP (IN of) (NP (NP (CD two) (JJ paired) (NNS chains)) (PP (IN of) (NP (NP (NNS units)) (VP (VBN known) (PP (IN as) (NP (NP (NNS nucleotides)) (, ,) (VP (VBN arranged) (PP (IN in) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (DT a) (NN helix))))))))))))))))) (. .)))
In 1953, the two teams announced their discovery that DNA consists of two paired chains of units known as nucleotides, arranged in the shape of a helix.
(ROOT (S (NP (NNP Dna)) (VP (VBZ consists) (PP (IN of) (NP (NP (CD two) (JJ long) (NNS chains)) (PP (IN of) (NP (NNS nucleotides)))))) (. .)))