The AMPS package of programs implements pair-wise global alignment with assessment of statistical significance by Monte-Carlo methods. It also implements position-specific weights and a variety of profile-based searching and alignment methods. However, the main function of AMPS is to produce multiple sequence alignments by a hierarchical method. Most features of the package are reviewed in [Barton, 1990]. CLUSTALW [Thompson et al., 1994] is an alternative to AMPS for multiple alignment. The program is available from many ftp sites.