The relative biological effectiveness of 14.5-MeV neutrons for the induction of gene conversion and mutation in yeast.
The relative biological effectiveness (RBE) and oxygen enhancement ratio (OER) were determined in the yeast Saccharomyces cerevisiae for the induction of gene conversion (the product of recombinational repair) and mutation (the product of error prone repair) by 14.5-MeV neutrons in comparison with 60Co gamma rays and 150 KVp X rays. Neutron irradiation in oxic or anoxic conditions induced significantly higher yields of convertants and mutants than sparsely ionizing radiations under the same conditions. RBEs for both gene conversion and mutation under anoxia were significantly higher than under oxic conditions. RBEs for mutant induction under anoxia were lower than the RBEs for gene conversion under the same conditions. The data support the hypothesis that the production of lesions leading to the genetic consequences of gene conversion and mutation differ in their dependence upon LET and the presence of oxygen during irradiation, and therefore the two DNA repair processes which produce these end points recognize, at least in part, different classes of damage.
D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D005214:Fast Neutrons; D005720:Gamma Rays; D005785:Gene Conversion / Q000528:radiation effects*; D009154:Mutation; D009502:Neutrons; D010100:Oxygen; D011831:Radiation Genetics; D012062:Relative Biological Effectiveness; D012441:Saccharomyces cerevisiae / Q000528:radiation effects; D014965:X-Rays
D003037:Cobalt Radioisotopes; D010100:Oxygen