Unformatted text preview: but it quickly becomes impractical as the number of sequences increases. What we need is a multiple sequence alignment , where all similar sequences can be compared in one single figure or table . The basic idea is that the sequences are aligned on top of each other in a common coordinate system. In this coordinate system, each row is the sequence for one protein, and each column is the 'same' position in each sequence. Each column corresponds to a specific residue in the 'prototypical' protein. As with pairwise alignments, there will be gaps in some sequences, most often shown by the dash '-' or dot '.' character. Note that to construct a multiple alignment, one may have to introduce gaps in sequences at positions where there were no gaps in the corresponding pairwise alignment. This means that multiple alignments typically contain more gaps than any given pair of aligned sequences....
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- Fall '10
- Chemistry, Sequence alignment, Multiple sequence alignment, Needleman, Smith & Waterman, Wunsch