Science Image (IMAGE) Salk Institute Caption Pictured is Day 17 of a cultured primate embryo; the various colors indicate markers of cellular differentiation (specialization). Credit Weizhi Ji/Kunming University of Science and Technology Usage Restrictions with credit and related coverage. 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.