( ( ( ( ( ( If ( they are ) ) ( , ( ( that chromosome ) ( is ( called ( a ( sex chromosome ) ) ) ) ) ) ) , ) and ) ( ( ( the genes ) ( on it ) ) ( are ( ( ( called ` ) ( sex linked ) ) ' ) ) ) ) . )
(ROOT (S (S (SBAR (IN If) (S (NP (PRP they)) (VP (VBP are)))) (, ,) (NP (DT that) (NN chromosome)) (VP (VBZ is) (VP (VBN called) (NP (DT a) (NN sex) (NN chromosome))))) (, ,) (CC and) (S (NP (NP (DT the) (NNS genes)) (PP (IN on) (NP (PRP it)))) (VP (VBP are) (VP (VBN called) (`` `) (S (NP (NN sex)) (VP (VBN linked))) ('' ')))) (. .)))
If they are, that chromosome is called a sex chromosome, and the genes on it are called 'sex linked'.
(ROOT (S (NP (JJ Sex-linked) (NNS traits)) (VP (VBP are) (VP (VBN located) (PP (IN on) (NP (NP (NNS genes)) (PP (IN on) (NP (NN sex) (NNS chromosomes))))))) (. .)))