[Genetic and somatic effects of ionizing radiation in humans and animals (comparative aspect)].
Genetic effects of ionizing radiation in the progeny of exposed parents could be conventionally subdivided on three main types. 1. Severe developmental disorders (fetus death, stillbirth, early postnatal mortality, malformation, hereditary disease, sterility). These effects are known to be caused by so called "gross" mutations (genomic, chromosomal, those of essential genes) with dominant harmful effects. Although found in rodents, insects, fishes they have not been found in humans. The proposal is made that the higher reproductive potency of a species the higher its tolerance for defective organisms. Due to strong selection against severe defects at the earliest stage of pregnancy, this genetic effect of radiation is likely to be difficult to detect in people. 2. Increased cancer risk manifested as elevated incidence of spontaneous tumors and increased sensitivity to carcinogenic agents. 3. Decreased fitness (non-carcinogenic negative health effects). These two last types of radiation genetic effects are presumably due to instability and functional inferiority of cell genome in the progeny of irradiated parents. The genetic background of these effects is suggested to be the load of induced minor mutations in regulatory genes (mini-, microsatelite loci) or/and epigenomic rearrangements of DNA in parental germ cells transmitted to progeny. These radiation genetic effects are much more obvious in animals as compared to humans. Apparently, they are difficult to find in humans because of their essential dependence on promotive (life style) factors, which are impossible to control in the offspring of irradiated people. A comparison of somatic (in irradiated organisms) and genetic (in the progeny of irradiated parents) effects of radiation provide evidence on the phenomenological as well as pathogenic similarity.
Vorobtsova
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Central Research Institute of Roentgenology and Radiology, St. Petersburg, 197758 Russia. radgen@IV9171.spb.edu
D000818:Animals; D005260:Female; D006801:Humans; D009154:Mutation; D011247:Pregnancy; D011839:Radiation, Ionizing; D013045:Species Specificity