Synchronous cultures of V79 Chinese hamster cells were irradiated in G1 with 300 rad of X-rays. Cells were collected for 2-h intervals after synchronization to include the first three post-irradiation divisions and were scored for chromosome aberrations. After the first post-irradiation division, asymmetrical exchanges were distributed according to the Poisson formula and both the asymmetrical exchange frequency and the acentric fragment frequency exhibited significant variations with collection time. Formulae derived from a previous mathematical analysis were used in conjunction with the aberration frequencies observed at the first, second, and third post-irradiation divisions to predict transmission and survival parameters for specific chromosomal aberrations. The probability, 2T, that an acentric fragment will be transmitted to a daughter cell at anaphase was found to be 0.57. The probability, W, that a two-break aberration (asymmetrical exchange) will be transmitted and observed at the next division was 0.56. Finally, the probability, P, that a cell will survive to a subsequent mitosis after losing a single acentric fragment was about 1.0 for one post-irradiation generation but somewhat less for two generations.
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