Shannon entrophy in ORF1 of Human NoV strains. The Shannon entropy at each position of the alignment is shown. Location of positions 3922 through 3973 of the alignment (which includes the AAACG motif) in a sequence region with zero entropy is shown by a red circle. A scheme showing the position of each gene in the NoV genome is shown below the graph. The location of the stem-loop is indicated sl.