Two hearts (IMAGE) University of California - San Diego Caption New research published in Developmental Cell from Emma Farley’s lab at UC San Diego has described the ability to predict which changes within enhancers, switches that control when and where our genes are expressed, lead to changes in organisms. The image depicts the way the researchers made just a single-letter change to an enhancer in sea squirts causing the organism to develop two hearts (highlighted in red). Credit Alexis Bantle and Granton Jindal, Farley Lab, UC San Diego Usage Restrictions Must be used in conjunction with Nature paper on enhancers and development. 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.