Figure 1

A progressive multiple sequence alignment. An example of progressive Multiple Sequence Alignment. (a) represents three input sequences (S1, S2, S3); (b) shows the pair-wise dynamic programming alignment of two sequences; (c) shows the order of the sequences to be aligned, where the leaves on right hand-side are the input sequences, the internal nodes represent the theoretical ancestors from which the sequences are derived, and the characters on the tree branches represent the missing/mutated residues; and (d) shows the pair-wise dynamic programming of two pre-aligned groups of sequences.