" Choanoflagellates are our closest single-celled relatives. The top image is a fluorescence micrograph of a dividing solitary choanoflagellate showing its DNA (blue) and flagella and mitotic spindle (green). A small choanoflagellate colony is shown below, with one of its cells dividing. Research from the Prehoda lab at the University of Oregon indicates that the connection between the flagella and division orientation may have been important for the evolution of organized multicellularity in animals. (Courtesy University of Oregon)"