Localization of gamma-rays induced chromatid breaks using a three consecutive staining technique

Three staining techniques (Giemsa, Q-banding and R-banding) are used consecutively to localize the breakage points in chromosomes of human lymphocytes, irradiated during G2-phase with gamma-rays, at doses ranging from 50 to 200 rad. The large majority, about 85% of the breaks, occurs at the interbands, between R- and Q-bands. The discrepancy of this result, with regard to previously reported ones, is attributed to the strong bias of analysis when only one staining technique is used.