Life on Earth has evolved through cataclysms, mass extinctions and climatic upheavals. However, certain biological forms seem to have gone through these ordeals without failing. Among them, a tiny organism intrigues as much as it fascinates scientists. Behind its apparent simplicity, the tardigrade hides an extraordinary capacity for resistance, now at the heart of a much greater ambition. By exploring the effects of the tardigrade gene on human cells, modern research is entering an area where survival is no longer just a matter of natural evolution.
Its secret lies in a unique survival mechanism: cryptobiosis. When water runs out or conditions become life-threatening, the tardigrade becomes almost completely dehydrated, folds its body in on itself, and enters a sort of biological sleep. In this state, its metabolism decreases its activity and the animal can thus remain inert for decades before coming back to life in contact with humidity.
But this exceptional survival is not just a matter of being put on pause. For several years, researchers have been trying to understand how its DNA, despite being exposed to extreme levels of stress, manages to remain intact. The issue goes beyond simple biological curiosity. Decoding the molecular mechanisms of tardigrade is perhaps a glimpse of the keys to a new cellular resistance, potentially applicable to humans.
Surprising resistance to radiation
In 2024, a Chinese team revealed an essential element of tardigrade resistance in the pages of Science, a study on a new species, Hypsibius henanensis. Using a so-called multi-omics approach, combining analysis of the transcriptome and the proteome, the researchers identified a gene called DODA1. The latter would promote the production of betalain, a type of pigment which exists mainly in plants, some fungi and bacteria and capable of neutralizing free radicals generated by radiation. Scientists have also identified tardigrade-specific proteins, such as TRID1, that accelerate the repair of damaged DNA. These discoveries are revolutionizing our vision of cell biology. Far from being simple microscopic curiosities, tardigrades become living models of resistance and adaptation.
Earlier, in 2016, a team of Japanese biologists published a study on the species in the journal Nature Communications Ramazzottius varieornatus. They identified a new protein, called Dsup (for Damage suppressor), capable of attaching to DNA and protecting it from radiation. By transferring the corresponding gene to human cells grown in the laboratory, the researchers observed a 40% reduction in the damage caused by X-rays. For the first time, a fragment of the genetic heritage of a tardigrade conferred measurable resistance to another species, proving that such a biological shield could cross the boundaries of life.
Applications raising ethical questions
Inspired by this discovery, researchers relayed by BBC are talking about reducing the side effects of anti-cancer treatments. Injected in the form of messenger RNA, the Dsup gene has already enabled mice to produce Dsup themselves and to better withstand doses of rays that usually destroy healthy tissue around cancer cells.
This extreme biology, where humans appropriate strategies from other species, nevertheless raises new questions. Should we strengthen our cells by integrating genes from other species, even if it means crossing an ethical limit?
