[SunilNagpal]

Can anyone answer this question?

At the transcription start site of a gene, any of the four nucleotides can occur with equal probability p. 
The Shannon Entropy S for this site would be? (Details in the image)

Given the fact that there is equal Probability for all 4 nucleotides, so p=0.25 or 1/4.

Now, all we have to do is fill the same into the given equation:

S= -[0.25*ln(0.25) + 0.25*ln(0.25) + 0.25*ln(0.25) + 0.25*ln (0.25)]

= -0.25[4ln(0.25)]
=-1*ln(0.25)
=-ln(0.25)
=-ln(1/4)
=-[ln(1) - ln(4)]
= -[0 - ln (2*2)]
= ln(2) +ln (2)
=0.69 + 0.69
= 1.38

I hope this is the way to go about it...