Microscopic Image of Zebrafish Larvae (IMAGE) University of Bonn Caption The distribution of the pigment cells (black) can be seen easily in the animals, which are only the size of an eyelash. If the function of the PSENEN gene (right) was disrupted, these collected in unusual places to form clearly visible patches -- similar to people with Dowling-Degos disease. Credit (c) AG Betz / Universität Bonn Usage Restrictions This photo may be used with the press release. 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.