In April 1986, the world witnessed one of the most catastrophic nuclear disasters in history when reactor four of the Chernobyl Nuclear Power Plant exploded, releasing massive amounts of radioactive material into the environment. The immediate impact was devastating, with severe repercussions for both the ecosystem and human health. However, amidst the tragedy emerged a remarkable tale of adaptation and resilience.

Three decades after the disaster, researchers have been examining the long-term effects of radiation exposure on the wildlife of Chernobyl. Among their discoveries were the startling observations of Eastern tree frogs displaying a conspicuous change in their appearance. Instead of the vibrant green hue typical of their species, some frogs appeared noticeably darker, almost black in coloration. Melanin, the pigment responsible for skin coloration in many organisms, is known for its ability to absorb and dissipate radiation energy. However, its role in protecting against ionizing radiation, such as that emitted by nuclear fallout, was less understood until now.

Through meticulous fieldwork and analysis, scientists, Germán Orizaola and Pablo Burraco uncovered a fascinating evolutionary response among the Chernobyl black frogs. Contrary to expectations, the dark coloration was not directly correlated with current radiation levels in the environment. In other words, it was not due to chemical reactions to the radiation such as burns. Instead, it appeared to be a heritable trait that had arisen in response to acute radiation exposure during the initial stages of the Chernobyl disaster.

Their findings suggested that frogs with darker pigmentation possessed a survival advantage from the radiation exposure. Melanin not only shielded their cells from damage but also enhanced their reproductive success. This can ultimately lead to an evolutionary shift over generations. In summary, natural selection favored those individuals with heightened melanin protection, allowing them to thrive even in the aftermath of such a catastrophic event.

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Image credit: Germán Orizaola and Pablo Burraco

https://scitechdaily.com/melanin-protection-chernobyl.../

https://www.livescience.com/black-frogs-evolution-chernobyl