( ( For example ) ( , ( ( ( the allele ) ( for ( ( ( ( blue eyes ) ( in humans ) ) and ) ( ( the allele ) ( for ( brown eyes ) ) ) ) ) ) ( ( are ( ( two alleles ) ( of ( the ( eye ( color gene ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (NP (NP (DT the) (NN allele)) (PP (IN for) (NP (NP (NP (JJ blue) (NNS eyes)) (PP (IN in) (NP (NNS humans)))) (CC and) (NP (NP (DT the) (NN allele)) (PP (IN for) (NP (JJ brown) (NNS eyes))))))) (VP (VBP are) (NP (NP (CD two) (NNS alleles)) (PP (IN of) (NP (DT the) (NN eye) (NN color) (NN gene))))) (. .)))
For example, the allele for blue eyes in humans and the allele for brown eyes are two alleles of the eye color gene.
(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))) (. .)))