10 Mar Columbia Scientists Study How DNA of Chornobyl Dogs Adapt to Toxic Environment
MedicalResearch.com Interview with:
Norman Kleiman, PhD, MS
Department of Environmental Health Sciences
Mailman School of Public Health
Columbia University, New York, NY
MedicalResearch.com: What is the background for this study?
Response: The 1986 Chornobyl nuclear disaster caused the evacuation of 300,000 persons from the cities and villages surrounding the nuclear power plant complex. Pets and belongings were left behind, and the Soviet authorities ordered all animals within the Chornobyl Exclusion Zone killed. Some dogs evaded destruction, and some 300+ descendants of these animals live primarily at two locations today, immediately surrounding the Nuclear Power Plant (NPP) complex and about 10 km away in Chornobyl city. What is relatively unknown to the general public is that Chornobyl is not a desolate, abandoned wasteland. Some thousands of individuals work there every day in continuing cleanup activities and at two new fuel reprocessing facilities built near the damaged reactor. These areas have been substantially remediated, and the average radiation levels are relatively modest. The dogs, which, while feral, are accustomed to human interaction, live near the workers and are not currently exposed to high radiation levels. In contrast to lower radiation levels, there is a toxic mixture of heavy metals, organics, pesticides, and unknown chemicals left over from years’ long cleanup efforts and the decay of a large former military-industrial complex at the NPP.
Since 2016, the NPP authorities have brought in teams of veterinarians and volunteers to spay, neuter, and vaccinate the dogs to protect the workers and deal with a growing population. At the same time, some scientists joined the teams to obtain various kinds of biospecimens (hair, urine, feces, blood, saliva, parasites) to examine the animals’ health and learn how this toxic environment may have affected them or their offspring. Since dogs are human companion animals and live closely with us, any information we learn about health risks to the dogs may be relevant to protecting human workers and inform us about the kinds of health risks posed by ecological and environmental disasters in the future.
MedicalResearch.com: What are the main findings?
Response: The study revealed, in granular detail, that the dogs in Chornobyl City and at the Nuclear Power Plant are genetically distinct from each other and from dogs who live outside the Exclusion Zone and that interbreeding between the Chornobyl City and NPP populations was very limited. Furthermore, the data suggests that there may be changes in specific genes that are biologically relevant to increased chances for survival, particularly genes regulating repair of DNA damage, movement through the cell cycle, and immune function.
MedicalResearch.com: How much these changes relate to human biology?
Response: One of the reasons this study is so important is that there are likely broad similarities between the adaptive response to toxic environmental exposures in dogs and humans. In other words, the same genes that respond to DNA damaging stress or damage the immune system are likely to be affected in humans and dogs. Thus the dogs serve as a “canary in a mine” to alert us to potential health hazards for humans and may provide clues as to how to mitigate these health risks in the future.
MedicalResearch.com: What recommendations do you have for future research as a results of this study?
Response: This work is only the first step in providing clues to the kinds of damage and adaptive responses that occur after large scale ecological and environmental disasters. The next step is to try and figure out if the genetic changes observed in the dogs is due to genetic “drift” occurring when separate populations don’t interbreed, or because of natural selection for certain traits that increase odds of survival. Furthermore, since the environment is a mixture of toxic exposures to radiation, metals, organics, pesticides, and chemicals, we hope to try and identify certain signatures or biomarkers that suggest which toxins are most relevant for health risks.
MedicalResearch.com: Is there anything else you would like to add? Any disclosures?
Response: When radiation exposure is combined with a complex toxic chemical mixture of uncertain composition, there are very real human health concerns raised for the thousands of people who continue to work within the Exclusion Zone on continuing cleanup efforts as well as at two newly constructed nuclear fuel reprocessing plants. Understanding the genetic and health impacts of these chronic exposures in the dogs will strengthen our broader understanding of how these types of environmental hazards can impact humans and how best to mitigate health risks.
Megan N. Dillon, Rachael Thomas, Timothy A. Mousseau, Jennifer A. Betz, Norman J. Kleiman, Martha O. Burford Reiskind, Matthew Breen. Population dynamics and genome-wide selection scan for dogs in Chernobyl.Canine Medicine and Genetics, 2023; 10 (1) DOI: 10.1186/s40575-023-00124-1
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