Radiation-Resistant Mutants at Chernobyl Pave the Way for Life on Mars

Radiotrophic beer is involved.

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May 7 2017, 5:00pm

Chernobyl fallout zone. Image: Diana Markosian

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Comic book logic dictates that a high dose of radiation will turn you in the Hulk, Godzilla, Radioactive Man, or any number of other radiation-induced superbeings. In real life, it's more likely to be a cause of deleterious mutations than a shortcut to enhanced abilities, as shown by major ecological damage in nuclear meltdown fallout zones, like Chernobyl and Fukushima.

These contaminated regions have become a popular destination for scientists interested in the immediate and long-term impact of radiation on wildlife, which has led to the formation of intriguing niche disciplines, like radioecology and radiobiology.

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Understanding how living organisms adapt to radiation doses has a range of applications, from medicine to conservation, but one of the most overlooked is preparation for long-duration human space missions and interplanetary colonization, both of which involve sustained exposure to higher radiation doses than what we experience on Earth's surface.

An experiment conducted on the International Space Station (ISS) last year examined this idea with the help of eight fungi species sourced from the Chernobyl exclusion zone. These strains sprung up in the wake of the 1986 meltdown, and two of them Cladosporium moulds—seem to prefer radioactive surfaces. The fungal samples were curated by a team led by Kasthuri Venkateswaran, a senior research scientist at NASA's Jet Propulsion Laboratory, who goes by Venkat for short.

Read More: Chernobyl Microbes Are Heading to the International Space Station

"The radiation seen at Chernobyl is high, but this black fungi popped up first [after the meltdown] compared even to the bacteria," Venkat told me over the phone. "That is how we selected those fungi, from such a radiation-rich environment. These fungi persisted due to some sort of protein-coding and biomolecule information that protect against the radiation level."

Would ingesting such a hardy mould give one radioactive superpowers? Not quite—or more accurately, not yet. The eventual goal of Venkat's research is to develop a fungi-based "sunblock" for outer space radiation that could be used to protect humans from the harmful effects of long-term exposure. The fungi was returned to Earth just a few months ago, so the results are preliminary, but Venkat and his colleagues are eager to pursue the research further.

"We have to take all the precautions before building a human habitation on Mars and beyond," he told me.

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In addition to helping humans become more radiation-resistant, studying the wildlife in fallout regions can also yield insight into engineering crops that can survive the radiation environment beyond Earth—especially highly irradiated worlds like those in the Jupiter system.

Cladosporium mould. Image: Medmyco

The Chernobyl exclusion zone is significantly more radioactive than the interior of proposed long-duration spacecraft, which makes it a bad direct analogy to outer space. But the ways in which crops develop tolerance to contaminated environments is rich with clues about surviving sustained doses of cosmic radiation.

"Radiation-resistant genes can be incorporated into yeast cells that produce beer so that humans are willing to go to space—they will have a better beer to drink," Venkat said, as one example.

Fallout zones are also useful testbeds for studying astrobiological questions about the search for aliens on other worlds, and the origins of life on our own planet. Flax crops grown at Chernobyl in the decades since the meltdown have demonstrated increasing resistance to contamination, for instance, leading some researchers to wonder if their genes are a kind of vestigial time capsule to the dawn of life on Earth.

"My favorite speculation is that when life on Earth was evolving, radioactivity was much more present on Earth's surface than is today," Martin Hajduch, a senior scientist at the Slovak Academy of Sciences' Institute of Plant Genetics and Biotechnology, said of his research into Chernobyl flax. "And so the plants are somehow 'remembering' it, [which is] what helped them to adapt in Chernobyl's radioactive area."

In this way, the world's worst nuclear disasters, which have threatened the health of our planet, may now help us understand our origins on Earth, and learn to survive the harsh conditions beyond it.

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