Researchers at the University of Stirling have found that animals in lakes closest to the Chernobyl nuclear reactor have more genetic mutations than those from further away, giving new insight into the effect of radiation on wild species.
DNA analysis of freshwater crustaceans, called Daphnia, revealed greater genetic diversity in lake populations that experienced the highest radiation dose rates following the accident in 1986. Radiation is the primary cause of these genetic mutations, according to Dr Stuart Auld, who led the research.
Dr Stuart Auld
Dr Auld, of Stirling’s Faculty of Natural Sciences, said: “Chernobyl is a natural experiment in evolution, because the rate of genetic mutation is higher, and all evolutionary change is fuelled by mutations.
“Normally you have to wait for generations to see the effect of the environment on mutations, and most mutant animals are pretty damaged so don’t live long. By sequencing non-coding DNA – bits of genetic code that don’t actually affect the form or function of the organism – we were able to uncover these mutations.
As part of her PhD, Dr Jessica Goodman collected the crustaceans using a kayak and net from lakes at varying distances from Chernobyl. She flew the samples back to the lab at Stirling, where Dr Auld’s team isolated and analysed the DNA.
"Humans are way worse than radiation!"
Dr Auld continued: “In a world affected by climate change, we really need to understand nuclear energy as an option, and its potential effects on natural populations.
“We know that exposure to acute radiation is terrible, but actually low levels are nowhere near as bad as we think. And many of the animals around Chernobyl have actually done very well, because the humans left – and it turns out we are way worse than radiation!”
The research was assisted by June Brand at the University of Stirling and Gennady Laptev from the Ukrainian Hydrometeorological Institute in Kiev. It was funded by the Natural Environment Research Council.
The paper ‘Radiation-mediated supply of genetic variation outweighs the effects of selection and drift in Chernobyl Daphnia populations’ is published in the Journal of Evolutionary Biology.