( ( Development ( of ( ( ( a ( prominent chin ) ) ( in ( ( humans and ) lack ) ) ) ( of ( one ( in apes ) ) ) ) ) ) ( ( may ( have ( been ( caused ( ( ( ( by ( neoteny ( -LRB- ( ( retention ( of ( ( juvenile traits ) ( in adults ) ) ) ) -RRB- ) ) ) ) and ) not ) ( by ( selection ( favoring ( ( an ( adaptive trait ) ) ( -LRB- ( ( Gould , ) 1977 ) ) ) ) ) ) ) ) ) ) ) ; ) )
(ROOT (S (NP (NP (NNP Development)) (PP (IN of) (NP (NP (DT a) (JJ prominent) (NN chin)) (PP (IN in) (NP (NNS humans) (CC and) (NN lack))) (PP (IN of) (NP (NP (CD one)) (PP (IN in) (NP (NNS apes)))))))) (VP (MD may) (VP (VB have) (VP (VBN been) (VP (VBN caused) (PP (PP (IN by) (NP (NP (NN neoteny)) (PRN (-LRB- -LRB-) (NP (NP (NN retention)) (PP (IN of) (NP (NP (JJ juvenile) (NNS traits)) (PP (IN in) (NP (NNS adults)))))) (-RRB- -RRB-)))) (CC and) (RB not) (PP (IN by) (NP (NP (NN selection)) (VP (VBG favoring) (NP (NP (DT an) (JJ adaptive) (NN trait)) (PRN (-LRB- -LRB-) (NP (NNP Gould)) (, ,) (NP (CD 1977)))))))))))) (: ;)))
Development of a prominent chin in humans and lack of one in apes may have been caused by neoteny (retention of juvenile traits in adults) and not by selection favoring an adaptive trait (Gould, 1977;
(ROOT (S (NP (JJ Adult) (NNS humans)) (VP (VBP lack) (NP (NP (DT some)) (PP (IN of) (NP (NP (DT the) (VBG defining) (NNS traits)) (PP (IN of) (NP (NNS chordates))))))) (. .)))