Putative stem cells in the hemolymph and in the intestinal submucosa of the solitary ascidian .

Background: In various ascidian species, circulating stem cells have been documented to be involved in asexual reproduction and whole-body regeneration. Studies of these cell population(s) are mainly restricted to colonial species. Here, we investigate the occurrence of circulating stem cells in the solitary a member of the Styelidae, a family with at least two independent origins of coloniality.