Relationship between the body's adaptation to heat and the modifying effect of extreme temperature on the effect of radiation. III. Role of genotype and environment in determining the intensity of the mutation process
Tikhomirova, M.M.
Genetika 16(3): 470-477
1980
ISSN/ISBN: 0016-6758 PMID: 6772524 Document Number: 161424
The modifying action of extremal temperatures (33 degrees C, 37 degrees C and 0 degrees C) on the effect of radiation (dominant lethals) was demonstrated in Canton-S and heat-resistant (T-32) stocks of Drosophila. The effect depended on genetic adaptation. Successive action of irradiation (406 rad, 137Cs) and extremal temperature in Canton-S stock have given more than additive effect (the after-effect was +13, +14 and +15%), the same treatment in the T-32 stock have produced lower than additive effect (the after-effect was -11, -10, -16 and -19%). The role of genotype and environment, i.e. ontogenetic and genotypic adaptation, in determination of modifying action of temperature on the radiation effect was differentiated. The effect was different under equal treatments of females of the heat-resistant stock developing under different temperature conditions. If the after-effect was negative under development temperature of 32 degrees C, it always was more than additive (the after-effect was +20, +50, +13, +40) under 25 degrees C. Similar pattern was observed for X-chromosome losses. Temperature 37 degrees C enhanced the radiation effect regardless of development temperature (the after-effect was 150 and 130%), and temperature 33 degrees C enhanced the radiation effect only if fly development occurred at 25 degrees C (the after-effect was 200%). Thus, ontogenetic adaptation takes an important part in determination of mutagenesity of environmental factors.