Figure 1.
Three types of motif representation in bidirectional promoters. Motifs in the overrepresented category occur more often (e.g., four times) than the sum of occurrences in two unidirectional promoters (e.g., 2 + 1 = 3 times). Motifs in the shared category occur as often (e.g., three times) as the sum of occurrences in two unidirectional promoters. Motifs in the underrepresented category occur less often (e.g., once) than the sum of occurrences in two unidirectional promoters.
