From The Heart: How Cells Divide To Form Different But Related Muscle Groups

Using the model organism Ciona intestinalis, commonly known as the sea squirt, researchers have uncovered the origins of the second heart field in vertebrates. Vertebrate hearts form from two distinct cell populations, termed first heart field and second heart field. From these fields are derived, respectively, the left ventricle and the right ventricle and outflow tract of the heart. The lineage relationship between these cell types was uncertain but mysteriously, a number of reports linked cells in the second heart field to muscle cells in the lower jaw in birds and mammals.