Alive and kicking. The dogs from the nuclear power plant exclusion zone that survived the disaster have turned their offspring into walking laboratories. They could hold the key to understanding how the immune system works and improving cancer treatments.
An explosion damaged the cooling system of reactor number 4 at the Chernobyl nuclear power plant (then in the Soviet Union; today on the border between Ukraine and Belarus) on April 26, 1986. Out of control, it started a chain reaction. The 2,000-ton lid flew into the air. Like an erupting volcano, absolute horror began to emanate in the form of radioactive isotopes: invisible, odorless, lethal. Hundreds of thousands of people were evacuated, leaving their pets behind. Almost forty years later, no one has been able to return. But the dogs are still there, alive and well.
They are the descendants of those who survived the crazed radiation of the first months and the gunfire from soldiers, who were ordered to kill them so they would not spread the stealthy poison that infiltrated their lungs and stuck to their paws and fur when they came into contact with the contaminated soil. Today they roam freely around the exclusion zone, a restricted perimeter of about 30 kilometres around the plant.
They begged for food from guards and a few daring tourists until the war in Ukraine militarized the cursed wasteland. A concrete sarcophagus surrounds the reactor. And radiation levels, though still some thirty times normal in many places, are no longer lethal in the short term. Despite its attenuated malignancy, Chernobyl remains a branch of hell. But it is also one of the most enigmatic places on the planet. And an open-air evolutionary laboratory.
It was not just dogs that thrived (and several hundred even found shelter in the ruins of the power station; wild, but healthy). Many other species have prospered. And that is something that puzzles scientists. In fact, radiation had poisoned the milk of cows; shrunken the brains of birds; spread tumors and malformations left and right. Moles with cataracts, sterile bees…
An estimated 1,000 stray dogs live in the Chernobyl exclusion zone. Many of them are descendants of dogs that survived alone in the exclusion zone after the 1986 evacuation.
In the midst of that ecological catastrophe, a light at the end of the tunnel appeared in 2016, when two Spanish researchers, Germán Orizaola and Pablo Burraco (University of Oviedo), found a surprising frog. It should have been bright green, but it was black. It had managed to protect its skin with a shield of melanin. Nature, which is wise for some reason, must have considered that if melanin (the pigment that makes us tan) is good against ultraviolet radiation, why not against ionizing radiation from cesium? It worked.
The Garden of Eden, nuclear version
Other mammals have colonised this improbable post-apocalyptic Eden: wild horses, elk, deer, lynxes… (In Fukushima, another nuclear wasteland, wild boars.) But it is canids, both dogs and wolves, that may hold the key to unraveling the mystery of how they do it and answering the million-dollar question: how do they defy cancer despite daily exposure to radioactivity that, on average, sextuples the limits considered safe?
The latest study was published by Princeton University. And it is very promising. Biologist Cara Love and her team traveled to the exclusion zone to take blood samples from the population of wolves and other canines. They fitted them with collars with a GPS device and a dosimeter. This way they knew where they moved and how much radiation they received. The researchers had a certain advantage, since the complete genome of almost all dog breeds has already been deciphered, and the DNA of gray wolves, foxes, coyotes… has also been sequenced.
In addition, we have identified many genes that are targets for tumors. So the idea was to see if the Chernobyl canines have genes altered by radiation. And if these mutations, instead of killing them, make them stronger. The bonus? We can draw lessons that can be useful to humans, because dogs are not only our best friends, but we share three out of four genes with them.
The bottom line is that these wolves appear to be fairly immune to cancer. That is, they are less likely to get it, and if they do, to survive it. Yet they are at the top of the food chain, which means they not only absorb pollution from the environment, but eat contaminated animals that have themselves been fed on toxic grasses. And yes, their genome has mutated — for the better! Their immune systems are altered in a way similar, Love says, to that of cancer patients receiving radiation therapy.
Their genome has mutated… for the better! They have an altered immune system similar to that of cancer patients who receive radiotherapy.
With one notable difference: they are not immunosuppressed, as is often the case with cancer patients. On the contrary, they appear to be strong and their population density is seven times higher than in natural reserves. “Our theory is that these wolves are undergoing a kind of accelerated process of natural selection; that is, that, among the generations that lived during and immediately after the catastrophe, some individuals had a mutation that made them more resistant: these were the ones that survived and passed on their genes to their descendants, who already had a natural protection that could have become stronger from one generation to the next,” explains Love.
Many questions remain unanswered. Only fifteen generations have passed since the accident. Is that enough to trigger a process that usually takes thousands or millions of years? Another study by the University of South Carolina (2023) also found that the genome of the hundreds of dogs roaming around the exclusion zone had undergone mutations, although in this case it could not be linked to radiation (as it was not the purpose of the research), but to inbreeding, as these dogs live in isolation and reproduce among themselves. There are many eyes (and many hopes) on Chernobyl.
Author:CARLOS MANUEL SANCHEZ
Date: Friday, June 28, 2024| Updated 01/07/2024, 12:14h
Source: Abc.es
Imagen de Wendelin Jacober en Pixabay.
Nutrigenomics Institute is not responsible for the comments and opinions included in this article
