A COMPARISON OF METHODS FOR CALCULATING DNA DOUBLE-STRAND BREAK INDUCTION FREQUENCY IN MAMMALIAN-CELLS BY PULSED-FIELD GEL-ELECTROPHORESIS

Pulsed-field electrophoresis (PFGE) has become one of the most widely used methods for the evaluation of radiation-induced DNA double-strand breaks (dsb). In most studies a simple quantification of DNA migratio n from the well in the gel has been used as the correlate with dsb for mation. Here we have compared such a method, as calibrated with I-125- labelled UdR, with two methods which involved the analysis of the dist ribution of sizes of DNA fragments migrating in the gel. We conclude t hat the three methods produce similar absolute values for dsb inductio n frequency. It is not clear which is the single method of choice but the comparision of the analyses increases the information which can be derived from PFGE experiments.