Chernobyl's canine survivors: How dogs evolved—and thrived—in the aftermath of a nuclear disaster

Mankind witnessed one of the most catastrophic nuclear disasters in history when the explosion at the Chernobyl Nuclear Power Plant in Ukraine shook the world in 1986. The horrifying disaster not only claimed lives but also displaced thousands, leaving an indelible mark on humanity. While the Chernobyl nuclear disaster has been extensively studied and discussed, a lesser-known result of the tragedy lies in its canine survivors. As reported by IFLS Science, the population of dogs in the city evolved into a genetically distinct population, setting them apart from other pooches around the globe.

Although the reasons behind these genetic mutations remain somewhat of a mystery to date, researchers revealed that the rapid evolution of these Chernobyl dogs may not have been caused by increased mutations. When the nuclear explosion happened nearly 40 years ago, the release of radioactive nuclides led to increased levels of toxic contaminants. The outlet claims that following the disaster, around 120,000 people were evacuated from the particular area. Remarkably, due to the mass displacement of people, many dogs were left to survive on their own in the radioactive zones surrounding the power plant.

However, against all odds, the dogs somehow managed to form a resilient population that continues to thrive even today. Moreover, recent estimates claim that around 800 semi-feral dogs now roam the Chernobyl region, including in some of the most highly contaminated areas. Interestingly, these dogs have undergone such significant genetic changes that researchers can now identify them only by looking at them. This, they believe, is a direct result of the environmental contamination that the canines have been exposed to over generations. Additionally, when researchers examined the mutation rate and the number of mutations in two well-established dog populations within that area, they found no evidence that these mutations were the main factor responsible for their genetic differences.

The researchers explained, “With this study, we do not find evidence of an increased mutation rate for the Nuclear Power Plant population of dogs through chromosomal aberrations, increased microsatellite diversity, or an increase of more recently derived alleles. Therefore, the mutation does not appear to be the cause of the previously identified genetic differentiation between these two geographically close populations of free-breeding dogs." Notably, even though the exact cause of this genetic diversity remains unclear, the team of researchers found some evidence suggesting that directional selection may be playing a role. However, further research can only confirm this theory.

Meanwhile, the dogs living in Chernobyl provide a unique opportunity for scientists to study how radiation affects genetics. It is because these dogs have been exposed to high levels of radiation that they could offer insights into how similar environmental factors might impact human health. As the study authors explained, "[They] may serve as effective sentinels for human health effects arising from toxic environmental exposures." Consequently, Chernobyl's dogs provide a unique and valuable resource for human mutation studies.

It is pertinent to mention that dogs aren't the only animals affected by the harsh conditions in Chernobyl. Other species such as songbirds have also been impacted because of the nuclear disaster. For example, the songbirds living in the Exclusion Zone (CEZ) have developed different gut microbiomes compared to those in other areas. Meaning? Well, the bacteria found in their digestive systems are unique to this environment. Similarly, tree frogs in that area have undergone color changes, possibly as a result of radiation or other environmental factors. On a related note, the wolves too have evolved a different immune system, which could help them cope with the challenges of living in such a toxic environment.