In these embryos potential heart cells are labeled by green fluorescent protein, FGF signaling causes two of these cells to form heart (and express a red fluorescent reporter gene)
The Brad Davidson lab studies heart development in sea squirt, Ciona intestinalis. Ciona is a chordate and thus a member of our own phyla. This close evolutionary relationship makes Cionagenetically more similar to humans than other invertebrate model organisms. The single-chambered Cionaheart forms by similar processes as the vertebrate heart tube, but in the context of a highly simplified embryo (see banner image above). Ciona has only one copy of many key developmental genes that were later duplicated in the vertebrates, allowing stringent assessment of gene function. Additionally, low cell numbers permit unprecedented visualization of cell morphology and migration. Despite this simplicity, the fundamental program for early vertebrate heart development is conserved in Ciona.