Data source:  There are a large number of tools available both online and to download that use the data provided by the GO project. The vast majority of these come from third parties; the GO Consortium develops and supports two tools, AmiGO and OBO-Edit. AmiGO is a web-based application that allows users to query, browse and visualize ontologies and gene product annotation data. It also has a BLAST tool, tools allowing analysis of larger data sets, and an interface to query the GO database directly. AmiGO can be used online at the GO website to access the data provided by the GO Consortium, or can be downloaded and installed for local use on any database employing the GO database schema (e.g.). It is free open source software and is available as part of the go-dev software distribution. OBO-Edit is an open source, platform-independent ontology editor developed and maintained by the Gene Ontology Consortium. It is implemented in Java, and uses a graph-oriented approach to display and edit ontologies. OBO-Edit includes a comprehensive search and filter interface, with the option to render subsets of terms to make them visually distinct; the user interface can also be customized according to user preferences. OBO-Edit also has a reasoner that can infer links that have not been explicitly stated, based on existing relationships and their properties. Although it was developed for biomedical ontologies, OBO-Edit can be used to view, search and edit any ontology. It is freely available to download. The Gene Ontology Consortium is the set of biological databases and research groups actively involved in the gene ontology project. This includes a number of model organism databases and multi-species protein databases, software development groups, and a dedicated editorial office. The Gene Ontology was originally constructed in 1998 by a consortium of researchers studying the genomes of three model organisms: "Drosophila melanogaster" (fruit fly), "Mus musculus" (mouse), and "Saccharomyces cerevisiae" (brewer's or baker's yeast). Many other Model Organism Databases have joined the Gene Ontology Consortium, contributing not only annotation data, but also contributing to the development of the ontologies and tools to view and apply the data. Many major plant, animal and microorganism databases make a contribution towards this project. As of July 2019, the GO contains 44,945 terms; there are 6,408,283 annotations to 4,467 different biological organisms. There is a significant body of literature on the development and use of the GO, and it has become a standard tool in the bioinformatics arsenal.