The samples were brought to Jeffreys' lab in England, where they were analyzed to produce DNA fingerprints that establish identity and paternity. Studying each family's blood samples, the researchers used five different systems for monitoring mutations. They found that the frequency of mutation was twice as high in families from Mogilev than in families from England. Among the Mogilev families, children with the higher mutation rates lived in areas where the soil is most contaminated with radioactive cesium-137, another indication that radiation exposure might be causing the additional mutations. For now, the most Jeffreys and his colleagues can conclude is that the mutations seen in the human study will likely be passed along to future generations because they are germline in origin.
Larger questions loom.
Both scientists and the public wonder whether the high mutation rates will translate into greater health problems for future generations. That's a question the researchers cannot answer at this time. One problem is that Jeffreys and colleagues cannot draw upon past studies with similar findings. There aren't any. Despite decades of research, there is no evidence for increased mutation rates in the genome of residents of Hiroshima and Nagasaki since the atomic bombs were dropped on those cities in 1945.