Adaptation to ionizing radiation induced by prior exposure to very low doses.

In human and animal cells, an adaptive response has been found to make cells somewhat refractory to the induction of chromosomal damage by high doses applied subsequently. These responses can also be induced in vivo by irradiating animals with low, or chronic doses. In regard to cytogenetic damage, and presumably those mutations that are cytogenetic in origin, the induced response leads to the repair, or rejoining, of broken chromosome ends, which means that chromosome aberrations, deletional (or null) mutations, DNA double-strand breaks, and even cellular survival that is dependent upon the genetic (cytogenetic) integrity of the cell can be endpoints that will show an adaptive response to ionizing radiations.