Chernobyl’s feral dogs are genetically unique but not mutated

Wild dogs living near Chernobyl are genetically different from their ancestors who survived the 1986 nuclear power plant disaster, but these differences do not appear to be due to radioactivity-induced mutations. New discoveries are helping experts understand how ecological disasters affect the surrounding environment and how these effects spread over time.

Chernobyl reactor meltdown remains the worst nuclear disaster in history. The initial explosion killed two workers at the facility on April 26, 1986, but at least another 28 people died from acute radiation poisoning and related problems over the next three months. At least 9,000 cancer deaths in Ukraine, Belarus and Russia have occurred within several decades of the meltdown, and an approximately 1,000-square-mile exclusion zone still exists around the facility, which includes the abandoned city of Pripyat. In addition to the confirmed deaths, including: other long-term effects as numerous studies suggest, include contaminated water, plant damage, and birth defects in humans and animals.

The ecological damage remains difficult to understand, but the region was never completely devoid of life. Many animals survived even after undergoing radiation-induced genetic mutations – in particular, many pet dogs abandoned by their owners during hasty evacuation orders from Chernobyl. It is estimated that several hundred feral dogs currently live in this area, providing a unique opportunity to study how these populations are adapting to the massive and sudden environmental degradation.

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In study published last yearresearchers have identified clear genetic differences between feral dogs in the Exclusion Zone and dogs living just 10 miles away in Chernobyl. These included 391 genetic outlier regions between the two populations, some specifically related to DNA repair. However, according to their further investigation published in the journal PLOS Onethe team now says there is “no evidence” that these contrasts are the result of increased mutation rates.

The researchers reached their conclusions by analyzing the samples at the chromosome level, after which small gaps in the genome and differences between individual nucleotides were taken into account. In particular, they looked for evidence of abnormalities such as accumulated germline DNA mutations – changes in the DNA of reproductive cells that are passed from parents to offspring over many generations. Matthew Breen, a professor of comparative genetics in comparative oncology at North Carolina and a co-author of the study, likened the entire process to using the zoom function on a phone camera.

“We start with a wide shot of the subject and then zoom in,” Breen said attached declaration January 13. “We know that exposure to high doses of radiation, for example, can cause instability from the chromosomal level down.”

Breen noted that although the current dog population is more than 30 generations removed from the 1986 Chernobyl disaster, the team would likely still identify genetic mutations, for example, if they conferred some form of survival. However, scientists found no evidence of such abnormalities.

“(M)utation does not appear to be the cause of the previously identified genetic differentiation between these two geographically close populations of free-breed dogs,” the study authors conclude. “Given this, combined with previous work on breed composition, inbreeding, and comparisons with other free-breed dog populations, we have yet to identify the ultimate cause of this genetic variation.”

Megan Dillon, an NC State doctoral student and lead author of the study, believes that the first generation of dogs to survive Chernobyl may have done so because of certain genetic traits they already had – rather than acquired through a radioactive mutation.

“Maybe there was a huge selection pressure at the beginning, and then the dogs at the plant simply remained separated from the city population,” she said. “Investigating this issue is an important next step that we are currently working on.”

Their latest discoveries go far beyond dogs. Considering the number of generations of dogs that have survived since the nuclear meltdown, Dillon likened today’s population to humans “centuries removed from (those) present at the time of the disaster.”

But just because today’s Chernobyl dogs lack the genetic mutations created by the radioactive fallout doesn’t mean they – or the humans still working on the cleanup – are safe from health problems.

“Most people think of the Chernobyl nuclear accident as a radiological disaster in a desolate corner of Ukraine, but the potential adverse health effects are much broader,” added Norman Kleiman, study co-author and professor of environmental health sciences at the Columbia University School of Public Health.

Kleiman explained that in addition to radiation, other toxins such as lead powder, pesticides, asbestos and heavy metals have been released into the environment over the thirty years of remediation work undertaken by thousands of people.

“The importance of continuing to study environmental health aspects of such large-scale disasters cannot be overstated,” Kleiman said.

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