Screenshot of the species selection interface. The user can select all species or a subset of species. Taxa and species for which no sequences for the selected proteins/protein classes exist are greyed out (taxa selection, model organisms) or are invisible (tree). Each node of the tree can be expanded and collapsed. The auto-completion fields open and highlight the tree down to the taxon/species typed. Common names like "dog" are also supported. All sections of the page respond to changes. Example: Nothing is selected. User selects kingdom Fungi. This selects all phyla, classes, orders, species and model organisms that belong to Fungi. Also the portion of the tree below Fungi is selected. User deselects Ascomycota. All elements react accordingly. User selects Homo sapiens. User clicks 'Show' in the result section and is presented with a list of sequences from Homo sapiens and all Fungi, excluding Ascomycota (see Fig. 3).