Predicting Fate (IMAGE) University of Pennsylvania School of Medicine Caption Earliest cells that form the liver (blue) emerging from progenitor cells (yellow) in the early embryo (green). Credit Ken Zaret, PhD, Perelman School of Medicine at the University of Pennsylvania Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.