Chromosome Aberrations and the Theory of RBE

SummaryThe LET-dependence of chromatid-aberration production in pollen tubes of Tradescantia bracteata and the influence of oxygen on the process have been determined by track-segment experiments with protons and alpha particles in the LET∞ range up to about 100 kev/µ. The results are in good agreement with the concept that an aberration results from the interaction of two chromatid primary lesions and that a primary lesion is produced by a single energy-loss event in the DNA of a chromatid, probably affecting initially only one strand of the DNA. The data for breaks and gaps are explained most easily in terms of the exchange hypothesis of aberration formation.