American researchers concluded that tadpoles can increase the level of DNA repair gene products enough to make them among the most prevalent in their genomes. It helps them withstand excessive radiation, among other things.

Tychopods are unique invertebrates that are closely related to arthropods and onychophores (sometimes referred to as roundworms). These crumbs, with a body length of between 0.1 and 1.5 millimeters, are extremely hardy. For example, they can “revive” after decades of anabiosis (they can actually dry out their bodies, covering themselves with a waxy crust – this phenomenon is called anhydrobiosis) and, when favorable conditions arise, can quickly return to activity.

Tardigrades have a short “energetic” lifespan – from three to four months to several years, depending on the species. Instead, in the state of anabiosis, these children can withstand incredible loads – for example, they can stay at temperatures of minus 20 degrees Celsius for 30 years. They can even be boiled for an hour or placed in liquid helium at temperatures up to 271 degrees Celsius for eight hours. Pacificas can stay in the atmosphere consisting of hydrogen sulfide and carbon dioxide for a long time, as well as withstand pressures of up to six thousand atmospheres.

But most of all, these creatures are famous for the fact that they tolerate radiation very calmly. So a dose of 570,000 ber of ionizing radiation would kill only 50 percent of the tardigrades. For comparison: The semi-lethal radiation dose for humans is only 500 ber. That’s why tardigrades are cosmonauts’ favorite experimental organism. They place the unfortunates in open space conditions and then return them to the ISS. At the same time, almost all tardigrades usually survive such a massacre and are even capable of reproducing.

The genome of these detritus is relatively large relative to their size and position in the evolutionary tree. It contains approximately 215 million nucleotides; this is approximately twice that of nematodes (genome sizes considered typical for small invertebrates). It’s no surprise that tardigrades are constantly being studied to understand how they can tolerate radiation doses that would be lethal to most creatures.

For example, in 2016, Japanese scientists discovered that these creatures protect their DNA from ionizing radiation by stabilizing it with a special protein, Dsup. Researchers from the University of North Carolina (USA) conducted another study in which they examined tadpoles of the species. Hypsibius example. The findings were presented in the journal Current Biology.

Scientists have discovered that gamma radiation actually damages the tadpoles’ DNA, but they can restore it. The studied species have a specific and persistent response to ionizing radiation: it causes rapid upregulation of many DNA repair genes in tardigrades. Unlike humans, tadpoles can increase the level of DNA repair gene products to such an extent that they are among the most abundant gene products in animals.