Silver Bullet

Similar yet simpler than humans, zebrafish are often used as biological models for our tissues – providing life-saving clues to development and disease. Here, researchers examine patterns of melanin, a pigment also found in human skin, in the body of a young zebrafish. To achieve these fine details, researchers took the unusual step of coating the melanin in solid silver. The precious metal interferes with x-rays, allowing a technique called X-ray histotomography (similar to X-ray microtomography) to pick out the patterns. Computer software traces out the melanin in three dimensions producing a rainbow heat map which highlights more (red) and less (blue) pigmented regions. Melanin forms distinct patterns in skin cancers like melanoma often caused by genetic mutations. Studies in zebrafish with similarly mutated genes might reveal characteristic early markers for affected human cells.

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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• Image from work by Spencer R Katz and colleagues
• Division of Experimental Pathology, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in eLife, September 2021