Tardigrades—tiny eight-legged creatures nicknamed water bears—are famous for surviving conditions that would kill almost any other form of life. Now, researchers in China have discovered the genes that help them withstand extreme radiation. The finding could one day improve protection for astronauts on long-duration space missions.
These microscopic animals, measuring just 0.3 to 0.5 millimeters, have amazed scientists for centuries. They can endure near-absolute zero temperatures, crushing pressure, lethal radiation, and even the vacuum of space. First identified in the 17th century, they remain a subject of fascination because of their unparalleled resilience.
Surprisingly resilient creatures
Tardigrades thrive across the globe, from Himalayan peaks to deep-sea trenches. Their toughness comes from an extraordinary trick: a state called cryptobiosis. In this dormant mode, they dehydrate almost completely and suspend all metabolism, allowing them to outlast extreme environments. In 2007, they became the first known animals to survive in outer space, with about 68% enduring ten days of exposure. Scientists still don’t know the maximum time they can remain in this state.
In April 2019, a probe took a thousand tardigrades to the Moon, the only known animal to withstand the vacuum of space and lack of oxygen. © France Culture, YouTube
The secret of their resistance to radiation revealed?
In their latest study, Chinese scientists identified a new species, Hypsibius henanensis, and discovered thousands of genes that switch on when it faces radiation. Publishing in Science, they reported that blasting the animals with doses several times more lethal than what humans can endure triggered nearly 3,000 genetic responses related to DNA repair, cell division, and immune defenses.
One standout gene, named DODA1, enables tardigrades to produce pigments called betalains—powerful antioxidants that clear harmful chemicals generated by radiation inside cells. To test the impact, the team treated human cells with these pigments. The results were striking: treated cells survived radiation far better than untreated ones.
Encouraged by this, the researchers believe their work could lead to new ways of protecting astronauts against space radiation, a major hurdle for future missions to Mars and beyond. By borrowing from tardigrades’ unique biology, humanity may be one step closer to safer long-term space exploration.
