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According to the results of recent studies, parental exposure to ionizing radiation not only leads to mutation induction in the germline of irradiated animals but also affects their non-exposed offspring. These radiation-induced transgenerational effects belong to an epigenetic phenomenon that could not be defined as a transmission of altered phenotypes from the irradiated parents to their non-exposed offspring. In this review, we present the results of laboratory studies aimed to evaluate the transgenerational effects of parental irradiation on a number of traits in the offspring of exposed parents. The results of animal studies showing compromised viability, fertility and genome stability among the non-exposed offspring of irradiated parents are presented and discussed. So far, the epigenetic phenomenon of radiation-induced transgenerational effects has been established in laboratory studies. Future work should address the important issue of manifestation of radiation-induced transgenerational effects in populations inhabiting radioactive-contaminated areas, as well as the mechanisms of transgenerational effects. [ABSTRACT FROM AUTHOR]

The frequency of mutation is two times as high among children whose parents were exposed to irradiation during the Chernobyl accident in populous areas of the Mogilev district of Belarus than in controls. Five minisatellite probes were used to estimate the rate of mutation. The mutation rate is proportional to the surface contamination levels of cesium-137. Radiation doses in the rural population indicate thyroid exposure to I-131 of 0.185 Gy per person. The increase in minisatellite mutation rate is probably due to an initial exposure to I-131 or chronic exposure to Cs-137.

A retrospective sample survey of birth certificates from a Moscow maternity hospital over a 40-year period has revealed secular growth changes (involving mothers' stature, age at menarche, and four anthropometric traits in newborns) in two consecutive generations. Cohorts of mothers born in the period 1930-1949 showed high rates of acceleration. Age at menarche decreased in these cohorts at a rate of 12.5 months per 10 years, and a parallel gain in stature averaged 1.8 cm per 10 years; both rates were significantly higher than those for Western Europe. In later birth cohorts the acceleration in the maternal generation apparently ended. Anthropometric traits at birth (weight, body length, head and chest circumferences) show different patterns of secular changes from 1950 to 1990. According to multiple regression analysis, a temporal trend in the neonate body size might be mainly due to the parallel increase in mother's stature. The contribution of socioeconomic factors to the observed secular growth changes is discussed., During the past 100-150 years most industrialized countries have revealed a tendency toward increasing velocity of growth and development of children and greater adult stature (Grimm 1966; Cavalli-Sforza and Bodmer [...]

The molecular basis of species-specific differences in courtship behavior, a critical factor in preserving species boundaries, is poorly understood. Genetic analysis of all but the most closely related species is usually impossible, given the inviability of hybrids. We have therefore applied interspecific transformation of a single candidate behavioral locus, no-on-transient A (nonA), between Drosophila virilis and D. melanogaster, to investigate whether nonA, like the period gene, might encode species-specific behavioral information. Mutations in nonA can disrupt both visual behavior and the courtship song in D. melanogaster. The lovesong of [nonA.sup.diss] mutant males superficially resembles that of D. virilis, a species that diverged from D. melanogaster 40-60 mya. Transformation of the cloned D. virilis nonA gene into D. melanogasterhosts carrying a synthetic deletion of the nonA locus restored normal visual function (the phenotype most sensitive to nonA mutation). However, the courtship song of transformant males showed several features characteristic of the corresponding D. virilis signal, indicating that nonA can act as a reservoir for species-specific information. This candidate gene approach, together with interspecific transformation, can therefore provide a direct avenue to explore potential speciation genes in genetically and molecularly tractable organisms such as Drosophila.