Very high mutation rate in offspring of Chernobyl accident liquidators

Exposure to ionizing radiation has long been suspected to increase mutation load in humans. Nevertheless, such events as atomic bombing seem not to ha ve yielded significant genetic defects. The Chernobyl accident created a di fferent, long-term exposure to radiation. Clean-up teams (or 'liquidators') of the Chernobyl reactor are among those who received the highest doses, p resumably in some combination of acute and chronic forms. In this study, ch ildren born to liquidator families (currently either in the Ukraine or Isra el) conceived after (CA) parental exposure to radiation were screened for t he appearance of new fragments using multi-site DNA fingerprinting. Their s ibs conceived before (CB) exposure served as critical internal controls, in addition to external controls (non-exposed families). An unexpectedly high (sevenfold) increase in the number of new bands in CA individuals compared with the level seen in controls was recorded. A strong tendency for the nu mber of new bands to decrease with elapsed time between exposure and offspr ing conception was established for the Ukrainian families. These results in dicate that low doses of radiation can induce multiple changes in human ger mline DNA.