C Y T O G E N E T I C M E C H A N I S M S I N S I L K W O R M S
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constituents of cell nuclei; whereas recovery from primary injuries of
the cytoplasm occurs over a wide range of doses and is, therefore, only
of minor biological importance. With reference to morphogenetic problems, this general principle can be interpreted as the necessary result of
the structural and functional specialization of the nucleus and cytoplasm.
Irradiated
Nonirradiated
Nonheated
/ y
Heated 4 0 ° , 135 minutes
Chch
Normal fertilization
Androgenesis
Irradiated cytoplasm and nucleus; perished
Irradiated only cytoplasm; viable
FIG. 8. Viability of androgenetic males developing from ova with irradiated cytoplasm and nonirradiated nuclei versus lethality of normal hybrids possessing irradiated cytoplasm and nucleus.
The irreversibility and especially great perniciousness of radiation damage to the nucleus are determined by the fact that its replicating genetic
microstructures are unique and irreplaceable. It is just these peculiarities
of nuclear macromolecules which are connected with its function in
heredity and its key position in biosynthesis and morphogenesis. On the
contrary, the multiplicity, quantitative inconstancy, and mobility of
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constituents of cell nuclei; whereas recovery from primary injuries of
the cytoplasm occurs over a wide range of doses and is, therefore, only
of minor biological importance. With reference to morphogenetic problems, this general principle can be interpreted as the necessary result of
the structural and functional specialization of the nucleus and cytoplasm.
Irradiated
Nonirradiated
Nonheated
/ y
Heated 4 0 ° , 135 minutes
Chch
Normal fertilization
Androgenesis
Irradiated cytoplasm and nucleus; perished
Irradiated only cytoplasm; viable
FIG. 8. Viability of androgenetic males developing from ova with irradiated cytoplasm and nonirradiated nuclei versus lethality of normal hybrids possessing irradiated cytoplasm and nucleus.
The irreversibility and especially great perniciousness of radiation damage to the nucleus are determined by the fact that its replicating genetic
microstructures are unique and irreplaceable. It is just these peculiarities
of nuclear macromolecules which are connected with its function in
heredity and its key position in biosynthesis and morphogenesis. On the
contrary, the multiplicity, quantitative inconstancy, and mobility of