mRNA Molecules (IMAGE) University of Pennsylvania School of Medicine Caption Individual mRNA molecules (purple) come from a chromosome (blue) within a cell's nucleus (yellow). Credit Marshall Levesque, Raj Lab, Perelman School of Medicine, Penn 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.