Clusters of Human Embryonic Stem Cells (IMAGE) Weizmann Institute of Science Caption These are clusters of human embryonic stem cells that were differentiated to an early germ cell (PGC) state (colored cells). Each color reveals the expression of a different gene. (l-r) NANOS3, NANOG, OCT4 and, on the right, all three combined in a single image. Credit Weizmann Institute of Science 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.