Fishy Looks

We can learn a lot about our development from similar, simpler processes in very different creatures. Here, researchers look a zebrafish (Danio rerio) in the eye. A high-powered microscope maintains eye contact with the developing fish for over 24 hours, highlighting tiny structures [organelles] called iridosomes, clustered around the iris (red). Each iridosome is like a tiny molecular factory – where reflective guanine crystals (blue) mature, eventually producing beautiful iridescent patterns the fish. Humans don’t have iridosomes, but we do share other similar organelles involved in shaping and storing important chemicals. Using zebrafish to study this specific type of organelle develops may help to unravel human genetic disorders like Heřmanský–Pudlák syndrome, which can have wide ranging effects including impaired vision.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Video from work by Anna Gorelick-Ashkenazi and colleagues
• Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
• Video originally published with a Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0)
• Published in Proceedings of the National Academy of Science (PNAS), April 2026