Mutation ionizing radiation

Brcimer, L.H. (1988). Ionizing radiation-induced mutation. Br. J. Cancer 57, 6-18. 

Genetic Effect of Radiation—Inheritable change, chiefly mutations, produced by the absorption of ionizing radiation by germ cells. Genetic effects have not been observed in any human population exposed at any dose level. 

Growing tissues are most sensitive to ionizing radiation. DNA synthesis is inhibited, yet the action of x-rays is indirect. They produce free radicals, which in turn react with DNA and thus produce point mutations or chromosomal breaks. 

Acute biological effects of the Chernobyl accident on local natural resources were documented by Sokolov et al. (1990). They concluded that the most sensitive ecosystems affected at Chernobyl were the soil fauna and pine forest communities and that the bulk of the terrestrial vertebrate community was not adversely affected by released ionizing radiation. Pine forests seemed to be the most sensitive ecosystem. One stand of 400 ha of Pirns silvestris died and probably received a dose of 80 to 100 Gy other stands experienced heavy mortality of 10- to 12-year-old trees and up to 95% necrotization of young shoots. These pines received an estimated dose of 8 to 10 Gy. Abnormal top shoots developed in some Pirns, and these probably received 3 to 4 Gy. In contrast, leafed trees such as birch, oak, and aspen in the Chernobyl Atomic Power Station zone survived undamaged, probably because they are about 10 times more radioresistant than pines. There was no increase in the mutation rate of the spiderwort, (Arabidopsis thaliana) a radiosensitive plant, suggesting that the dose rate was less than 0.05 Gy/h in the Chernobyl locale. 

Radiation causes dominant lethal mutations in the medaka (Oryzias latipes) (Shima and Shimada 1991). Mosquitofish (Gambusia spp.) from radionuclide-contaminated ponds in South Carolina differed from conspecifics in reference ponds, as judged by the frequency of DNA markers, and this is consistent with the hypothesis that these DNA markers may originate from genetic elements that provide a selective advantage in contaminated habitats (Theodorakis et al. 1998). Ionizing radiation at low-level chronic exposure reportedly has no deleterious genetic effects on aquatic populations because exposure is compensated by density-dependent responses in fecundity (IAEA 1976). However, this needs verification. 

Sankaranarayanan, K. 1991a. Ionizing radiation and genetic risks II. Nature of radiation-induced mutations in experimental mammalian in vivo systems. Mutat. Res. 258 51-73. 

Thacker, J. 1990. Molecular nature of ionizing radiation-induced mutations of native and introduced genes in mammalian cells. Pages 221-230 in Ionizing Radiation Damage to DNA Molecular Aspects. Proceedings of a Radiation Research Society — UCLA Symposia Colloquium. Lake Tahoe, CA, January 16-21, 1990. Wiley-Liss, New York. 

SHIRLEY, B.W., HANLEY, S., GOODMAN, H.M., Effects of ionizing radiation on a plant genome analysis of two Arabidopsis transparent testa mutations, Plant Cell, 1992, 4, 333-347. 

L. Liang, M. S. Mendonca, L. Deng, S. C. Nguyen, C. Shao and J. A. Tischfield, Reduced apoptosis and increased deletion mutations at Aprt locus in vivo in mice exposed to repeated ionizing radiation. Cancer Res., 2007, 67(5), 1910. 

Lee JM, Bernstein A. p53 mutations increase resistance to ionizing radiation. Proc Natl Acad Sci USA 1993 90 5742-5746. 

When ionizing radiation affects just one nucleotide in a sequence, this may produce a point mutation. Most point mutations are of little consequence because the same protein or a functional variation is made anyway. However, some point mutations result in a nonsense message from which a nonfunctional protein is constructed, while other point mutations give a meaningful but changed message leading to a protein with altered properties. 

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