Radiation Causes Darker Skin Colors in Chernobyl Frogs, Area Radioactivity Does Not Affect Them Now

A study has shown that radiation causes other Chernobyl frogs to have darker skin colors, making them immune to current radioactive levels.

The 1986 nuclear reactor disaster at Chernobyl, or Chornobyl (as the preferred Ukrainian transliteration spells), caused radioactive fallout that accelerated the evolution of nearby species.

A study claims that the radiation from the Chornobyl mishap has caused the Eastern tree frog (Hyla orientalis) in Ukraine to change its skin color from green to black.

The authors wrote that at the time of the accident, skin coloration was darker in areas closest to those with high radiation levels, but it appeared that for Chornobyl tree frogs skin coloration was unaffected by current radiation levels.

The dorsal skin tone of tree frogs inhabiting the Chornobyl Exclusion Zone was noticeably darker than that of frogs living elsewhere.

Radioactive Isotopes from Chornobyl Nuclear Power Plant Mishap

On April 26, 1986, the Chornobyl nuclear power plant's reactor number 4 melted down and exploded. The reactor core then burned in the open for several days.

As a result, airborne radioactive contaminants were released and spread across much of nearby Europe, including Ukraine.

These radioactive isotopes, which are primarily fission byproducts, emit ionizing radiation that can damage DNA and result in genetic mutations.

These mutations can cause cancer and death, birth defects, or, in a small number of instances, benign mutations that are passed on to the next generation. This kind of evolution is fueled by radiation.

In the past, it has been observed that strong selective factors, like the radiation from Chornobyl or environmental pollutants, can cause quick adaptive responses, including in plants and fish.

Darker Skin Color

Researchers discovered that the darker coloration of the Ukrainian tree frogs may not have been the result of a random mutation, but rather an adaptive reaction to shield the frogs from the high radiation levels.

Melanin pigmentation has been suggested as a buffering mechanism against ionizing radiation. Dark skin tone is known to reduce DNA damage and neutralize free radicals, protecting against various types of radiation.

Read also: World's 11 Most Radioactive Places - the Consequences can be Devastating 

Defensive Melanin

The study's findings imply that exposure to intense ionizing radiation may have been selected for darker coloration in tree frogs from Chornobyl, which were most likely exposed at the time of the accident.

Many living things, including humans, have dark skin and eyes because of melanin, which can also lessen the harmful effects of radiation.

Melanin shields individuals from ultraviolet light and has been found to protect the body from ionizing radiation in fungi. Melanin absorbs and dissipates a portion of the radiation energy.

Reactive oxygen species are just one example of ionized molecules that can hunt and neutralize inside the cell. By taking these steps, individuals subjected to radiation have a lower chance of developing cell damage later on and a higher chance of surviving.

In essence, the frogs might have developed resistance to the radiation rather than randomly mutating to turn black as a result of the radiation.

The authors added that the underlying principles and evolutionary ramifications of the patterns observed here require further investigation. Regarding the dearth of field-based experiments as well as the small sample size employed in the experiment screening for liability in coloration, the team acknowledges the drawbacks of their field approach, Newsweek reports.

Related article: Chernobyl: Not The Only Wildlife Spot With a Wild Past (Or Present)