Apart from their disconcerting cuteness, tardigrades are famed for the fact that they’re nigh on indestructible. These tiny creatures are extremophiles, adapted for life in environments that would kill most other organisms. Different species demonstrate different resistances, and one of the most intriguing is some species’ ability to survive huge amounts of ionizing radiation—in some cases, over 1,000 times the dose that would be required to kill a human.
Earlier this year, scientists examined a species of tardigrade called Hypsibius exemplaris in the hope of understanding how it can withstand such huge doses of radiation. To their surprise, they found that the tardigrade hadn’t evolved some sort of way to shield its DNA from the damage caused by this radiation; instead, they showed a remarkable ability to repair that damage quickly and efficiently.
[Related: How super resilient tardigrades can fix their radiation-damaged DNA]
A new study, published October 24 in Science, investigates the radiotolerance of another species of tardigrade, Hypsibius henanensis. (This is a new species, discovered by the researchers themselves and named in honor of the Chinese province of Henan.) These tardigrades were exposed to heavy doses of gamma rays—high-energy photons that are one form of ionizing radiation—and researchers then studied how their systems responded.
They found that while H. henanensis demonstrates the same ability to repair damaged DNA as H. exemplaris, it also has a couple of other tricks up its sleeve.
The danger that ionizing radiation poses to living creatures comes from its ability to ionize atoms: a gamma ray photon carries enough energy that when it strikes an atom, it can essentially knock one of that atom’s electrons loose. If that atom happens to be part of a DNA molecule, the result can be a breakage in one or both of the delicate strands that wind into the famous double helix. Breakages of both strands are…
Read the full article here
