( These ( ( ( ( are ( represented ( by ( uppercase letters ) ) ) ) and ) ( can ( be ( listed ( by ( using ( ( ( ( env or ) printenv ) ( at ( the command ) ) ) prompt ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These)) (VP (VP (VBP are) (VP (VBN represented) (PP (IN by) (NP (JJ uppercase) (NNS letters))))) (CC and) (VP (MD can) (VP (VB be) (VP (VBN listed) (PP (IN by) (S (VP (VBG using) (S (NP (NP (NN env) (CC or) (NN printenv)) (PP (IN at) (NP (DT the) (NN command)))) (ADJP (JJ prompt)))))))))) (. .)))
These are represented by uppercase letters and can be listed by using env or printenv at the command prompt.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (VP (VBD represented) (PP (IN by) (NP (DT a) (JJ single) (NN letter)))))) (, ,) (NP (JJ dominant) (NNS alleles)) (VP (VBP are) (VP (VBN represented) (PP (IN by) (NP (JJ uppercase) (NNS letters))))) (. .)))