image: When grafted to a neutral embryonic region, untreated limb bud tips (left) form an incomplete axis, whereas retinoic acid-treated ones (right) are reprogrammed to form all the limb segments. This image relates to an article that appeared in the May 27, 2011, issue of Science, published by AAAS. The study, by Dr. Alberto Roselló-Díez of Centro Nacional de Investigaciones Cardiovasculares in Madrid, Spain, and colleagues was titled, "Diffusible Signals, Not Autonomous Mechanisms, Determine the Main Proximodistal Limb Subdivision." view more
Credit: CNIC