Center for Integrative Genomics

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Choanoflagellates

Choanoflagellates are microscopic, heterotrophic single-celled and colony-forming eukaryotes. Occupying diverse freshwater and marine ecosystems, choanoflagellates create a critical link between nanoplankton and larger organisms in the marine carbon cycle. In addition to their ecological role, choanoflagellates are among the closest unicellular relatives of animals and provide important insights into the origin and diversity of animal phyla.

Choanoflagellate

The distinctive architecture of choanoflagellates, with a collar of tentacles and a single apical flagellum, most resembles that of "collar cells" found in sponges and other animals. Using their flagella, choanoflagellates propel themselves through their aquatic environments, collecting bacteria and detritus on the walls of their collars. In fact, choanoflagellates are thought to be major players in the marine carbon cycle, breaking down bacteria and returning nutrients to the water.

Choanoflaggellate image The marine choanoflagellate Monosiga brevicollis was selected for genome sequencing because it is easily grown in the laboratory, is available in monoxenic (single species) culture, and has been thoroughly considered in phylogenetic studies. The complete M. brevicollis genome sequence will provide a foundation for reconstructing the early evolutionary history of multicellular animals and for interpreting the physiology of these ecologically significant organisms.