First Molecular Glimpse (IMAGE) Rockefeller University Caption Molecular markers delineate the different cell types within an attached human embryo, shown here 12 days after fertilization. A structure called the epiblast, for example, is shown in green. The key developmental landmarks observed using this novel system accurately match those of normal human development, up to 12 days after fertilization. Credit Gist Croft, Alessia Deglincerti, and Ali H. Brivanlou/The Rockefeller University Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. 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.