Ensembl produces and maintains evidence-based automatic annotation and incorporates manually curated annotation on selected eukaryotic genomes. Our annotation is based on mRNA, protein and functional genomics information. Ensembl provides valuable insights into variation within and between species, and allows users to compare whole genomes to identify conserved elements. It is integrated with several other important molecular resources, including UniProt, and can be accessed programmatically. Ensembl collaborates with genome sequencing centres and annotation groups around the world.