Chromosomal versus chromatid types of radiation-induced damage as a function of cell-cycle phase during irradiation. If a cell is irradiated during the G1
or early S phase when only 1 chromosomal homolog exists, a nonrepaired DNA-DSB (double-strand break) can lead to dicentrics, reciprocal
translocations and acentric fragments. During irradiation in late S and G2 phases, sister chromatids have duplicated and the DNA-DSB gives rise to
interchanges, triradials, or a chromatid deletion. Consequently, the type of chromosomal damage observed may also reflect the relative ability of cells to
utilize the nonhomologous end-joining (optimally used during G1) or homologous recombination (optimal in S and G2) repair pathways to correct the DNADSB. (From Nagasawa et al, 2010.)
Source: Molecular and Cellular Basis of Radiotherapy, The Basic Science of Oncology, 5e
Citation: Tannock IF, Hill RP, Bristow RG, Harrington L. The Basic Science of Oncology, 5e; 2016 Available at: http://mhmedical.com/
Accessed: July 31, 2017
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