The Mouse Adult Gross Anatomy Ontology and Mammalian Phenotype Ontology are downloaded weekly from the Mouse Genome Informatics databases at Jackson Laboratories (ftp://ftp.informatics.jax.org/pub/reports/index.html). For more information about these ontologies, see the MGI Publications Page at http://www.informatics.jax.org/mgihome/other/publications.shtml.
abnormally stretched or widened aperture of the luminal space of the endothelial lined dilation that is located at the arterial pole of the heart just above (distal to) the truncus arteriosus in mammalian embryos; it is the primordial vascular channel from which the aortic arches (and eventually the dorsal aortae) arise; the aortic sac is homologous to the ventral aorta of gill-bearing vertebrates