Waking illustration (IMAGE) University of California - Santa Cruz Caption Molecular interactions drive the biological clocks in our cells, synchronizing our bodies with the 24-hour cycle of night and day. Certain mutations can shorten clock timing, making some people extreme “morning larks” because their internal clocks operate on a 20-hour cycle. Credit Image created by Jonathan Philpott with Bing Image Creator Usage Restrictions For use only with news coverage of this research License Original 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.