The University of California Santa Cruz (UCSC) Genome Browser (genome.ucsc.edu) 
is a popular Web-based tool for quickly displaying a requested portion of a 
genome at any scale, accompanied by a series of aligned annotation "tracks". The 
annotations-generated by the UCSC Genome Bioinformatics Group and external 
collaborators-display gene predictions, mRNA and expressed sequence tag 
alignments, simple nucleotide polymorphisms, expression and regulatory data, and 
pairwise and multiple-species comparative genomics data. All information 
relevant to a region is presented in one window, facilitating biological 
analysis and interpretation. The database tables underlying the Genome Browser 
tracks can be viewed, downloaded, and manipulated using another Web-based 
application, the UCSC Table Browser. Users can upload personal data as custom 
annotation tracks in both browsers for research or educational use. This unit 
describes how to use the Genome Browser and Table Browser for genome analysis, 
download the underlying database tables, and create and display custom 
annotation tracks.