Evolution of NOTCH2NL Genes (IMAGE) University of California - Santa Cruz Caption As shown in this diagram, the NOTCH2NL genes arose through a duplication event in a common ancestor of humans, chimpanzees, and gorillas, but only became functional genes in the human lineage. Credit Sofie Salama Usage Restrictions For use only with news coverage of this research 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.