Definition 5 (Information)
The information carried by a DNA character or base in DNA sequence database D is defined as I(c) = -log|C|Pr(c,D), where |C| is the number of distinct characters in D and Pr(c) is the probability of c occurs in D.
For example, the occurrence probability of character A in Table 1 is Pr(A,D) = # of occurence(A)/|D|. So, the probability of character A is Pr(A,D) = 10/55 = 0.182 in our example database. Then, the information of character A in D is, I(A) = -log|C|Pr(A,D) = -log4(0.182) = 1.228.