Chernobyl Dogs Survive Without Evolving
Stray dogs left behind after the Chernobyl accident
are still living and reproducing, but not becoming more fit
People evacuated quickly after the world’s worst nuclear accident in April 1986 at Chernobyl, Ukraine. The exclusion zone, 2,600-square-kilometer area around the power plant, contains ghost towns of former schoolrooms, businesses and homes abandoned by residents. Only a few scientists have ventured in to study the aftereffects of radiation that shot up to 400 times higher than normal. One of them is Timothy Mousseau from the University of South Carolina, who published results of a 2011 study of the effects on birds (see 12 Feb 2011). This month, he published another research paper about “the dogs of Chernobyl.”
What Chernobyl’s stray dogs could teach us about radiation (Nature News, 3 March 2023). Commenting on the new study, Freda Kreier begins with a photo of cute pups carrying on their hard lives near the power plant. They were spared after initial fears in 1986 that dogs should be killed to prevent them from carrying radiation out into surrounding communities.
The immediate impacts of the accident at Chernobyl were obvious: around 30 people who worked at the power plant and fire fighters who attended after the disaster died of radiation poisoning within a few months of the catastrophe, according to the World Health Organization. And in the surrounding areas, pine trees withered and many insect species vanished, unable to survive in the radioactive soil.
What is less clear is how low levels of lingering radioactive material from the disaster affect the plants and animals around Chernobyl today. A handful of studies have reported unusually high genetic mutation rates in barn swallows and fruit flies in the vicinity of the reactor, which is now entombed in a steel and concrete sarcophagus.
Mousseau took pity on the dogs and provided some veterinary care, but also finds it useful to study them to learn about the long-term effects of radiation exposure. He has taken blood samples from some of the dogs to assess mutational damage. The dogs may have been suffering from poor diet, the news article says;
But teasing out which genetic changes in the dogs are caused by radiation and which are caused by other factors — such as inbreeding or non-radioactive pollutants — won’t be easy, Brenner cautions. The team acknowledges these challenges, but the researchers argue that their detailed knowledge of these dogs’ ancestry, as well as knowledge of the levels of radiation different dogs were historically exposed to, “provides an ideal focus group for our future studies”.
Regarding the story, Laura Ungar reported 3 March 2023 on Phys.org that the researchers were looking for genetic markers indicating evolution:
“We can compare them and we can say: OK, what’s different, what’s changed, what’s mutated, what’s evolved, what helps you, what hurts you at the DNA level?” Ostrander said. This will involve separating non-consequential DNA changes from purposeful ones.
The study’s results were published early this month:
> Spatula et al., with Timothy Rousseau, The dogs of Chernobyl: Demographic insights into populations inhabiting the nuclear exclusion zone, Science Advances, 3 March 2023.
The authors explain why studying the dogs of Chernobyl provides a unique research opportunity.
The abundance of wildlife populations within the CEZ was substantially reduced following the accident, and although some species appear to have recovered, likely due to a lack of human disturbance, many have not. One of the greatest concerns is that continued environmental pollution, including radiation and heavy metal poisoning, may raise or lower genetic species diversity depending on directional selection, bottleneck events, or alteration of migration patterns. Increased genetic diversity via elevated mutation rates may be more likely in highly mutagenetic environments, such as that of Chernobyl, or other radioactive places on Earth. Conversely, a reduction in the mating population from the initial effects of the disaster, including high doses of radiation and fires, may markedly reduce genetic diversity. To date, no population genetic studies of Chernobyl organisms have included large-bodied mammals, such as canines. Thus, nonhuman mammals in the CEZ are greatly understudied, despite their potential to offer powerful insights into the history and survival of life in this hostile environment.
The domestic dog presents an interesting case in this regard, as little is known about the origin of the free-roaming dog populations in the Chernobyl region or how canine populations survived after the explosion…..
The team found two genetically-distinguishable populations of dogs depending on their proximity to the nuclear power plant, but teasing out the ancestry of the dogs has been difficult. “The idea that the dogs now living in the greater Chernobyl area are descendants of the pets left behind by evacuees after the nuclear disaster remains uncertain,” the authors say. People have been moving back into the area, some of them bringing dogs as pets. Which dogs are descendants of those left behind? Which are descendants of free-roaming dogs? The work of identifying causes of genetic changes in the dogs begins with this initial study, but will take time to analyze.
Uniquely, each individual population in the Chernobyl region has experienced differential levels of contamination that are well recorded, offering additional advantages in experimental design. Our identification of shared genomic haplotypes and establishment of modern versus ancestral origins present a target for future genetic studies of radiation signatures. The Chernobyl dog population has great potential for informing environmental resource management studies in a resurging population. Its greatest potential, however, lies in understanding the biological underpinnings of animal and, ultimately, human survival in regions of high and continuous environmental assault.
An Informative Silence
The most surprising part of the paper, though, is what it does not say. There is no mention of evolution, fitness, or selection other than the one passing reference to “directional selection” which was only stated as a possibility. It may “raise or lower species diversity,” they said, hedging their bets. One would think that the Chernobyl accident offered a prime opportunity to study dog evolution, especially for an evolutionary ecologist like Mousseau, but the team could not even identify “survival loci” in the genes. Their “Phylogenetic Analysis” only goes back to 1989. Certainly there were no indications of beneficial mutations, novelties or innovations. No wings sprouted on these dogs, and no mutant ninja turtles appeared in the forests.
Evolutionary biologists should have anticipated these outcomes. Decades of radiation experiments on fruit flies in the 20th century never increased fitness. The only outcomes of radiation showered on Drosophila were fruit flies that were sick, deformed, or dead. No scientist witnessed an origin of species. The surviving fruit flies were still fruit flies. The Chernobyl dogs are still dogs. If it weren’t for repair mechanisms, none of them would be alive today. “The dogs’ continued presence in the area shows that they were able to survive and breed, even while living near the reactor, ‘which is remarkable‘,” said a geneticist.
As reported here 21 April 2016, wild animals and people have been moving back into the exclusion zone and are doing better than expected. The initial death toll rapidly tapered off. This doesn’t imply that taking a radiation bath is advisable, but thankfully living organisms contain multiple sophisticated mechanisms to repair their DNA.
Maybe the evolutionists should promise to evaluate the dogs after a million years. That would give them cover. They can appeal to futureware to preach, “Evolution is a fact, and if the evidence doesn’t confirm it today, it will tomorrow.” Why not? That storytelling method has worked for over 160 years to string along the gullible into remaining loyal to King Charley.