The University of California Santa Cruz Genomic Browser (http://genome.ucsc.edu/; Karolchik et al. 2003 ) is among the most popular databases for querying and retrieving genomic sequences of interest. It currently provides access to genomic assemblies from 23 organisms, including 10 vertebrates, 8 insects, 2 nematodes, a sea squirt, baker's yeast, and the SARS virus. Whether genomic regions are retrieved from an existing database or sequenced locally, there are an increasing number of options for analysis and annotation. Several computational tools allow identification of genes and exon boundaries in genomic sequences. GENSCAN (Burge and Karlin 1997) , TWINSCAN (Korf et al. 2001) , MZEF (Zhang 1997) , and Gene Recognition and Analysis Internet Link (GRAIL; Uberbacher and Mural 1991) are among the most popular. Most gene finding programs were optimized to predict genes in sequences from mammalian models; as a result accuracy is sometimes reduced when using sequences from more divergent organisms or nonvertebrates. These programs use different strategies and are based on current, but incomplete understanding of gene structure. Therefore, predictions from multiple programs should be combined computationally to enhance accuracy and confidence (Rogic et al. 2002) .