The MGI Expression  Detected ontology contains genes expressed in specific anatomical structures at specific developmental stages (Theiler stages) in mouse. The information is primarily obtained by curators from the literature. The anatomy for each developmental stage is represented by a directed acyclic graph that gives a hierarchy of anatomical terms and their relationships.
The human MGI Expression ontologies are derived by mapping expression information from all genes in the mouse ontologies to their human orthologs. In general, it is unclear if the expression pattern of the orthologous human gene has diverged.
Statistics can now be found in the footers of each table in the GREAT web output.
All ontology data was downloaded and built between Oct 14, 2011 and Feb 18, 2012.
GREAT v1.8 MGI Expression: Detected statistics are available here.
GREAT v1.2 MGI Expression: Detected statistics are available here.
Bult, C.J., et al. The Mouse Genome Database (MGD): mouse biology and model systems, Nucleic Acids Res. 2008 Jan; 36(Database issue):D724-8.