If the second site X is actually random, any bases are possible, the information content is: C 2 = 1-1/4·log(4)·4 = 1-1 = 0 or C 2 = log 2 (4)-1/4·log 2 (4)·4 = 2-2 = 0bit If the probabilities of the third site T are 1/2 for T, 1/4 for A, 1/4 for G, the information content of third site can be calculated as: The more conserved the sequence, the more the information content. The amount of information of the sequence is determined by how much you know to write the sequence. If you know it is a DNA sequence and the probability distribution of each site of the known sequence, you need information I = H unknown -H known = 6-3.5 = 2.5 bits to write the sequence AXT. The information of the sequence is 2.5 bits.