Using the model organism Ciona intestinalis, commonly known as the sea squirt, researchers at the University of California, Berkeley, have uncovered the origins of the second heart field in vertebrates.

Sea squirts are bag-like gelatinous creatures whose full genome has been sequenced--one that shares 80 percent of its genes with humans. Though its body is clearly more primitive than creatures with backbones and spinal columns, the sea squirt nevertheless offers a valuable ...