Caption
Embryo of the solitary sea squirt Ciona intestinalis (Chordata, Tunicata), a benthic marine invertebrate and plankton filter-feeder, observed using an epifluorescence microscope. The embryos have been coloured using a DNA-marker (light blue) to highlight the cell nuclei, and various RNA probes (dark blue/black), in order to uncover the expression profile of the genes involved in the development of the epidermis and peripheral nervous system. Its relative anatomical and genetic simplicity, as well as its phylogenetic similarity to vertebrates, make Ciona intestinalis a commonly used model organism for the study of embryo development.
