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Biophysics
Romashov, D.D., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Golovinskaia, K.A., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Beliayeva, V.N., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Bakulina, E.D., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Pokrovskaia, G.L., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Cherfas, N.B., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
1. (1) In experiments with groundling and carp, it has been established that X-irradiation of the sperms and fertilization by them of normal spawn gives a degree of damage to the developing embryos (mortality, malformation, disturbances in embryonal mitoses) which increases as the radiation dose rises only within certain limits (for the groundling 2000-6000 r). Beyond this limit the damage is lessened and despite an increase in the dose of radiation a gradual return to normal is observed in terms of mortality and percentage chromosome breaks. Further, although the degree of deformation diminishes, the percentage of deformed embryos remains at a constant extremely high level: single normal individuals make their appearance at very high doses of radiation starting from 100,000 to 200,000 r. The picture of the so-called Hertwing effect is observed in these phenomena. 2. (2) A maximum degree of damage to the embryos is matched by a maximum number of breaks in the sperm chromosomes. The subsequent mitigation of the damaging effect is associated with destruction of the sperm nucleus as a whole (pycnosis, disintegration) and its genetic deactivation; in such cases control over development is effected solely by the undamaged maternal nucleus (haploid gynogenesis). The appearance of normal, viable carp and groundlings for the strongest radiation doses indicates that in this case there occurs diploid gynogenesis. The low number of such normal individuals shows that the mechanism of diploid restoration is not sufficiently regulated, as is also suggested by the cytological findings. 3. (3) The application of temperature shocks to the groundling spawn prior to fertilization or just after fertilization with sperm irradiated with 200,000 r raised the percentage of diploid gynogenetic individuals from 0·5 to 7 per cent on average and in individual experiments up to 36 per cent (of the number of embryos hatched). Cytological investigations showed that a high degree of inhomogeneity of chromosome sets is observed in embryos produced by fertilization of normal spawn by sperms irradiated with doses of 100,000-200,000 r: there were isolated individuals with a diploid set of chromosomes, haploids were often encountered, mosaic embryos making up the vast majority. On cold shocks applied to the spawn, diploids were found much more often than haploids, though mosaics still predominated. 4. (4) Experiments with Prussion carp (Carassius auratus gibelio) of a unisexual line showed that the ability to undergo natural gynogenesis enables the spawn of this fish to withstand the destructive action of sperm exposed to ionizing radiations irrespective of the size of the dose employed. © 1960.
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Diploid radiation gynogenesis in fish
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Romashov, D.D., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Golovinskaia, K.A., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Beliayeva, V.N., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Bakulina, E.D., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Pokrovskaia, G.L., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Cherfas, N.B., Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow, Russian Federation, Institute of Pond Pisciculture, the R.S.F.S.R., Moscow, Russian Federation
Diploid radiation gynogenesis in fish
1. (1) In experiments with groundling and carp, it has been established that X-irradiation of the sperms and fertilization by them of normal spawn gives a degree of damage to the developing embryos (mortality, malformation, disturbances in embryonal mitoses) which increases as the radiation dose rises only within certain limits (for the groundling 2000-6000 r). Beyond this limit the damage is lessened and despite an increase in the dose of radiation a gradual return to normal is observed in terms of mortality and percentage chromosome breaks. Further, although the degree of deformation diminishes, the percentage of deformed embryos remains at a constant extremely high level: single normal individuals make their appearance at very high doses of radiation starting from 100,000 to 200,000 r. The picture of the so-called Hertwing effect is observed in these phenomena. 2. (2) A maximum degree of damage to the embryos is matched by a maximum number of breaks in the sperm chromosomes. The subsequent mitigation of the damaging effect is associated with destruction of the sperm nucleus as a whole (pycnosis, disintegration) and its genetic deactivation; in such cases control over development is effected solely by the undamaged maternal nucleus (haploid gynogenesis). The appearance of normal, viable carp and groundlings for the strongest radiation doses indicates that in this case there occurs diploid gynogenesis. The low number of such normal individuals shows that the mechanism of diploid restoration is not sufficiently regulated, as is also suggested by the cytological findings. 3. (3) The application of temperature shocks to the groundling spawn prior to fertilization or just after fertilization with sperm irradiated with 200,000 r raised the percentage of diploid gynogenetic individuals from 0·5 to 7 per cent on average and in individual experiments up to 36 per cent (of the number of embryos hatched). Cytological investigations showed that a high degree of inhomogeneity of chromosome sets is observed in embryos produced by fertilization of normal spawn by sperms irradiated with doses of 100,000-200,000 r: there were isolated individuals with a diploid set of chromosomes, haploids were often encountered, mosaic embryos making up the vast majority. On cold shocks applied to the spawn, diploids were found much more often than haploids, though mosaics still predominated. 4. (4) Experiments with Prussion carp (Carassius auratus gibelio) of a unisexual line showed that the ability to undergo natural gynogenesis enables the spawn of this fish to withstand the destructive action of sperm exposed to ionizing radiations irrespective of the size of the dose employed. © 1960.
Scientific Publication
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