( ( For example ) ( , ( ( ( a letter ) ( preceded ( by ( dots 4-5-6 ) ) ) ) ( ( represents ( a ( single ( uppercase letter ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (NP (NP (DT a) (NN letter)) (VP (VBN preceded) (PP (IN by) (NP (NNP dots) (CD 4-5-6))))) (VP (VBZ represents) (NP (DT a) (JJ single) (NN uppercase) (NN letter))) (. .)))
For example, a letter preceded by dots 4-5-6 represents a single uppercase letter.
(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))))) (. .)))