A transitory, membrane-less structure consisting of cell organelles (e.g., mitochondria, centrioles, Golgi bodies, and endoplasmic reticulum) and macromolecules (e.g., RNAs, proteins, lipids, and ribonucleoproteins) found in the early ooplasm (q.v.) of a wide variety of vertebrate and invertebrate species. A Balbiani body generally originates near the nuclear envelope (q.v.) and differentiates into a well-defined mass often surrounded by mitochondria, before breaking down to release its constitutents into the ooplasm. It is thought to function in the organization and transport of RNAs and organelles that later become localized in specific regions of the ooplasm. Balbiani bodies show heterogeneity in number, morphology, and composition among different species and are named after the French biologist, Edouard-Gérard Balbiani (1823–1899), who was among the first to describe them. Also called Balbiani vitelline body. See mitochondrial cloud, sponge body, cytoplasmic localization.
Subjects: Genetics and Genomics.