Exposure fractionation effects for X-ray-induced dominant lethals in immature (stage-7) oocytes of Drosophila melanogaster: A re-analysis |
| |
Authors: | K. Sankaranarayanan W.S. Volkers |
| |
Affiliation: | 1. Department of Radiation Genetics and Chemical Mutagenesis, The Netherlands;3. Department of Human Genetics, State University of Leiden, Sylvius Labortaories, Wassenaarseweg 72, Leiden, The Netherlands;2. The J.A. Cohen Interuniversity Institute for Radiopathology and Radiation Protection, Leiden, The Netherlands |
| |
Abstract: | Young (0—4-h-old) Drosophila melanogaster females were X-irradiated with single or fractioned exposured over a range up to 6000 R and the induction of dominant lethals in immatuer (stage-7) oocytes was studied. The results show that (i) the frequencies of dominant lethals are higher after single than after fractionated exposures; (ii) at any given exposure level, the higher the number of fractions, the lower is the frequency of dominant lethals; (iii) conserquently, the reduction in dominant lethality relative to single exposures increases with increasing number of fractions; and (iv) this relative reduction in dominant lethality approaches a maximum value when the magnitude of the single X-ray exposure approaches zero (i.e., when tha egg survival after single X-ray exposure approaches 100%); the maximum, however, are different for the different fractionation regimes, being higher with increasing number of fractions.These findings are consistent with the assumed kinetics of X-ray induction of dominant lethality in stage-7 oocytes. It is shown that it is possible to predict the expected relative reduction in dominant lethality after fractionation, from appropriate dominant lethal data from single unfractioned exposures. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|