ALG2 mutation (IMAGE) Heidelberg University Caption The retina of the medaka fish with a mutation in the ALG2 gene shows progressive loss (magenta colours) of the rod cells (left) in contrast to wild-type specimens. This symptom is also known as night blindness or retinitis pigmentosa. Credit Clara Becker Usage Restrictions This image may be used only in connection with the contents of this press release, and the source of the image must also be cited. 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.