Harvard Medical School researchers have discovered that a pigment contained in the egg of the South African claw-toed frog is indispensable for development. Witout the pigment, called biliverdin, which is present in yolk platelets, the egg cannot go through dorsal axis formation. In its absence, Xenopus laevis embryos develop into headless, eyeless, spineless lumps of tissue. “For many decades, biliverdin has been considered to have no biological significance or function,” said principal investigator Kenneth Falchuk, Harvard Medical School associate professor of medicine at Brigham and Women’s Hospital. “There’s going to be a lot of interest now to identify what biliverdin’s functions are.” A study by Falchuk’s research team was published in the Jan. 8, 2002, issue of the Proceedings of the National Academy of Sciences.