( ( Typically ( genes ( ( ( ( have ( two alleles ) ) , ) but ) ( in ( this case ) ) ) ) ) ( there ( ( are three ) ; ) ) )
(ROOT (S (SBAR (S (ADVP (RB Typically)) (NP (NNS genes)) (VP (VP (VBP have) (NP (CD two) (NNS alleles))) (, ,) (CC but) (VP (PP (IN in) (NP (DT this) (NN case))))))) (NP (EX there)) (VP (VBP are) (NP (CD three))) (: ;)))
Typically genes have two alleles, but in this case there are three;
(ROOT (S (NP (NP (DT The) (NN majority)) (PP (IN of) (NP (JJ human) (NNS genes)))) (VP (VBP have) (NP (QP (CD two) (CC or) (JJR more)) (JJ possible) (NNS alleles))) (. .)))