Fin Experiment (IMAGE) University of Chicago Medical Center Caption The image on the left shows the fin bones of a wild type medaka fish. The image on the right is a medaka with the gli3 gene knocked out. The knockout fish has extra proximal radial bones (labeled pr in teal) and additional fin rays, signs of the fish version of polydactyly. Credit Image from Letelier et al., PNAS, 2021 Usage Restrictions May only be used to report on this paper 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.