Some of the greatest inventions of my lifetime have been from looking at nature and copying. I found out tadigrades in outer space have the ability to repair their own DNA when exposed to radiation thousands of time higher than what it would take to kill a human being. Can the tardigrade's genome be mapped and the section of DNA responsible for repairing radiation damage be duplicated? Would that be a good thing? Could a stem cell with that section of DNA make our astronauts safer?
Would that be a good thing?
Recent research from the Samson lab at MIT suggests that there are side effects from amplifying the DNA repair mechanism.
Hyperactivity of a base-excision repair (BER) protein called AAG in mice caused a positive feedback loop in DNA repair signaling that triggered macrophages to attack retinal cells, leading to a cycle of increased inflammation, photoreceptor (PR) necrosis, and ultimately blindness.
From the linked paper:
In this study, we demonstrated that programmed necrosis and subsequent inflammation are important mediators of AAG-dependent alkylation-induced PR cell loss in male mice... We showed that PR cells present necrotic morphology and oxidative DNA damage after the induction of PR cell death with alkylating agents; furthermore, we observed that PARylation in the PR nuclei is associated with the release of HMGB1, increased macrophage infiltration, and elicitation of an inflammatory response.
Another research project looked at a DNA repair protein called ATM in mice, where hyperactivity or overexpression may be implicated in Alzheimer's and Huntington's diseases. Knock-down mutants show reduced expression of this protein and reduced neural damage.
Ignoring the larger ethical questions of splicing genes into human beings, and the technical questions of how to get said genes inserted, transcribed, and translated in the right place at the right time in the right way, it would likely require considerable study to see what the systematic effects might be from expression of tardigrade or other organisms' DNA repair genes in humans.
At the very least, these papers suggest that the biology is complex enough that turning up the dial on repair machinery could cause serious health problems downstream, as much as it might confer greater protection from radiation or other environmental damage.