Summary
-
1.
Currently available data on chromosome elimination in Cecidomyiidae are still inadequate to support any definite conclusions regarding its immediate causes. It seems that some evidence on the mechanism of elimination could be obtained from observation of the behavior of E chromosomes in complete absence of spindle. To bring about such absence of spindle, ultraviolet microbeams would appear promising, since they have already been used to destroy spindles in cells of other organisms.
-
2.
For irradiation the embryos of Rhabdophaga batatas Walsh were chosen. It was established that in this species 2 S+E=40 and 2 S (for female)=8. Elimination of 30-odd chromosomes regularly occurs in the fifth cleavage. Embryos were irradiated with 8μ and 16μ heterochromatic ultraviolet microbeams not only in this fifth cleavage but also in the fourth, in which elimination was never observed. The irradiated regions were small parts of somatic cytoplasm or small parts of germ cells.
-
3.
The effects of irradiation were multifold: complete degeneration of nuclei in the vicinity of irradiated cytoplasm; disappearance of spindle and formation of quasi-rosettes; multipolar mitosis. The polar substance present in germ cells was often severely damaged and fragmented. All these effects are evidently indirect.
-
4.
In mitoses thus deprived of spindles, the separation of chromosomes into daughter chromatids was suppressed but some of their active movements persisted. All chromosomes were gathered into a quasirosette, which afterwards divided into two quasi-rosettes. The daughter quasi-rosettes moved apart and formed telophase nuclei. In both irradiated divisions (fourth and fifth) E chromosomes behaved in exactly the same manner as S chromosomes; they showed the same kind of peculiar movement and were incorporated into telophase nuclei. Suppression of elimination of E chromosomes in the fifth division can be regarded as one more indirect effect of irradiation to be added to the list above.
-
5.
These results show that elimination of E chromosomes does not result from failures in chromosomal spindle fibers or from intrinsic morphological defects in the centromeres. The fact that elimination can be suppressed by indirect action of ultraviolet light strongly supports the assumption that elimination occurs because of chemical changes in adjacent cytoplasm that are injurious to the centromeres of E chromosomes. Most probably the indirect action of ultraviolet interferes with the production of some substance that is normally injurious to the centromeres in the fifth division.
-
6.
Since in Cecidomyiidae the general features of the metabolism are known to be stable up to the mid-blastoderm stage, it would appear that the chemical changes involved in elimination cleavage are probably quite specific.
Similar content being viewed by others
References
Bloom, W., R. E. Zirkle and R. B. Uretz: Irradiation of parts of individual cells. III. Effects of chromosomal and extra-chromosomal irradiation on chromosome movements. Ann. N.Y. Acad. Sci. 59, 503–513 (1955).
Brown, S. W., and F. D. Bennett: On the sex determination in the diaspine scale Pseudaulacaspis pentagona (Targ.) (Coccoidea). Genetics 42, 310–523 (1957).
Geyer-Duszyńska, I.: Elimination of chromosomes in Cecidomyiidae (Diptera). Bull. Acad. pol. Sci. Cl. 2 6, 371–375 (1958).
—: Experimental research on chromosome elimination in Cecidomyiidae (Diptera). J. exp. Zool. 141, 391–448 (1959).
—: Chromosome behavior in spermatogenesis of Cecidomyiidae (Diptera). Chromosoma (Berl.) 11, 499–513 (1961).
Matuszewski, B.: Chromosome behavior during oogenesis in gall midge, Mikiola fagi Hart. (Cecidomyiidae, Diptera). Bull. Aead. pol. Sci. Cl. 2 7, 101–104 (1960).
Nicklas, R. B.: An experimental and descriptive study of chromosome elimination in Miastor spec. (Cecidomyiidae, Diptera). Chromosoma (Berl.) 10, 301–336 (1959).
Schrader, F.: Cytological and evolutionary implications of aberrant chromosome behavior in harlequin lobe of some Pentatomidae (Heteroptera). Chromosoma (Berl.) 11, 103–128 (1960).
Uretz, R. B., W. Bloom and R. E. Zirkle: Irradiation of parts of individual cells. II. Effects of an ultraviolet microbeam focused on parts of chromosomes. Science 120, 197–199 (1954).
Uretz, R. B., and R. P. Perry: Improved ultraviolet microbeam apparatus. Rev. sci. Instr. 28, 861–866 (1957).
—, and R. E. Zirkle: Disappearance of spindles in sand-dollar blastomeres after ultraviolet irradiation of cytoplasm. Biol. Bull. 109, 370 (1955).
Zirkle, R. E.: Partial-cell irradiation. Advanc. biol. med. Phys. 5, 103–146 (1957).
-Structure of mitotic spindle. In Symposium on Molecular Biology, Univ. Chicago Press, p. 321–331, 1959.
—, W. Bloom and R. B. Uretz: Use of partial cell irradiation in studies of cell division. Proc. Int. Conf. Peaceful Uses Atomic Energy (Geneva) 11, 273–282 (1956).
Author information
Authors and Affiliations
Additional information
This work was performed under a fellowship of the Rockefeller Foundation while the author was on leave of absence from Warsaw University, Department of Cytology. The experiments were supported financially by the U. S. Atomic Energy Commission and by the Abbott Research Fund, University of Chicago.
Rights and permissions
About this article
Cite this article
Geyer-Duszyńska, I. Spindle disappearance and chromosome behavior after partial-embryo irradiation in Cecidomyiidae (Diptera) . Chromosoma 12, 233–247 (1961). https://doi.org/10.1007/BF00328921
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00328921