Protein-coding gene structures result from the integration of a variety of prediction methods and data sources followed by manual review and revison by WormBase curators. tRNAs are predicted by tRNAscan, and other non-coding RNA transcripts are taken from a variety of literature sources. The purple and blue colors indicate transcripts on the forward and reverse strands respectively. If sufficient room is available between features, gene models end with a triangle; if not a small arrow is used. Grey areas represent 5' and 3' UTRs of protein-coding transcripts, assigned automatically using the extents of overlapping ESTs and full-length cDNAs. The UTR predictions have not been reviewed by WormBase curators, and some are known to contain artifacts.