1. From the Laboratory of Developmental Biology (P.D. E. Lee, A.K., R.S., S.Y., L.L., C.W.L.) and Animal Magnetic Resonance Imaging Core (S.A.), National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md; Children’s National Heart Institute, Children’s National Medical Center, Washington, DC (P.D., A.K., M.D., L.L.); National Museum of Health and Medicine, Human Developmental Anatomy Center, Washington, DC (E. Lockett): and Congenital Anomaly Research Center, Kyoto University...