Whether a researcher is working on a genome project, or is cloning and characterizing a gene of interest, the ability to manipulate, analyze, and annotate sequence data is becoming increasingly important. It is evident by now that efficiently performing the above operations on thousands or millions of base pairs by hand is so difficult as to be impossible, and computer programs that do sequence analysis are becoming more and more ubiquitous in laboratories practicing molecular biology. MacVector™ , from Oxford Molecular Group, Campbell CA, is one such computer package. It is an integrated comprehensive sequence analysis program that runs on the Macintosh. It provides all of the most commonly used nucleic acid and protein analysis tools and also provides access via the Internet to the public Entrez databases at the National Center for Biotechnology Information (NCBI). At the time of writing, the version of MacVector available was 6.5. MacVector also comes with a module for contig assembly, called AssemblyLIGN. AssemblyLIGN will not be discussed here.