Figure 4.

Pictograms of positional nucleotide frequency distributions observed around donor site (left column) and acceptor site (right column). Pictograms of the distributions derived after the first iteration are shown in the top panels of panel pairs, for the distributions derived at the algorithm convergence—in the bottom panels. Values (in bits) of the information content of the first-order positional Markov model derived from the aligned sequences are shown next to the pictograms. (The pictograms were drawn by the software utility available at genes.mit.edu/pictogram.html).