Mouse Embryos with Snake Genes (IMAGE) Cell Press Caption This image depicts mouse embryos with the ZRS from cobra or python inserted into their genomes, replacing the normal gene regulator. Their truncated limb development is visible in the comparative bone scans. Credit Kvon et al./Cell 2016 Usage Restrictions Credit Required. 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.