Radiation induced chromosome aberrations: some biophysical considerations.

The implications of recent results using FISH chromosome painting and soft X-ray exposures for the mechanisms of chromosome aberration formation are discussed. It is concluded that the evidence in favour of exchange aberrations arising from one radiation induced chromosome break has increased to the point where a 'change in paradigm' from the older breakage-reunion hypothesis needs to be taken seriously into account. A potential role for recombinational repair of DNA double strand breaks, as known in yeast, in the formation of aberrations in mammalian cells is presented and the relationship between DNA repair studies and radiation cytology is emphasized.