We have now spent 12 years trying to sort out the effects of a radioactive environment on the local wildlife. We have performed a variety of experiments in the Zone. In one of our earliest studies, we found that the resident mouse population did not have any obvious chromosomal damage. We wondered whether the absence of injury could be explained by some sort of adaptive change, perhaps a more efficient DNA-repair mechanism, after many prior generations of exposure to radiation. But when we transplanted wild mice from uncontaminated regions into cages in the red forest and then examined their chromosomes, they were likewise unaffected by the radiation. In at least this respect, the mice seemed to have a natural « immunity » to harm from radiation. We repeated the cage experiments with Big Blue transgenic mice—which carry a gene that glows « blue » if it undergoes a mutation—and radiosensitive mice to look for evidence of chromosome breakage, genetic aberrations and changes in gene expression. The genetic impacts proved to be subtle and not likely to threaten the rodent’s reproductive success or longevity. We also compared the genetic variations of populations inside the Zone with those from relatively uncontaminated areas, and we found no evidence of increased mutation rates from exposure to radioactivity.

Ronald K. Chesser, Robert J. Baker, « Growing Up with Chernobyl », American Scientist, Nov-Dec 2006 Vol 94, Num 6, p. 542