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The action of X-rays on the cell

II. The external variable

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Summary

From a study of X-ray-induced chromosome changes inTradescantia pollen grain division it is found that:

1. One-break chromosome changes (i.e. fractures) vary as the square of dose, or a slightly higher power.

2. Two-break changes (i.e. new reunions) vary approximately as the 1·5 power.

3. Minute fragments are intermediate in behaviour.

4. All types of change increase as a slightly higher power of dose when the duration of the dose is kept constant than when the intensity is kept constant. Since this ‘intensity effect’ applies equally to one- and two-break changes it cannot be the result of ‘healing’ of the broken ends, or of competition between restitution and new reunion.

5. From this it appears that irradiation not only breaks the chromosomes but also inhibits reunion of broken ends. This inhibiting effect increases with increasing dose, is greater when a particular dose is administered more rapidly, and affects both restitution and new reunion.

FromTradescantia pollen tube divisions it is found that:

6. There is additional evidence that minute fragments include a large proportion of small rings.

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References

  • Barber, H. N. (1940). The suppression of meiosis and the origin of diplochromosomes.Proc. roy. Soc. B,128, 170–85.

    Google Scholar 

  • Darlington, C. D. &Upcott, M. B. (1941). Spontaneous chromosome change.J. Genet. 41, 297–338.

    Google Scholar 

  • Fabergé, A. C. (1940). An experiment on chromosome fragmentation inTradescantia by X-rays.J. Genet. 39, 229–48.

    Article  Google Scholar 

  • Lewis, D. (1941). Genetical studies in pears. VI. Pollen-tube growth and incompatibility.J. Genet. (in the Press).

  • Muller, H. J. (1940). An analysis of the process of structural change in chromosomes ofDrosophila.J. Genet. 40, 1–66.

    Article  Google Scholar 

  • Muller, H. J.,Makki, A. I. &Sidky, A. R. (1939). Gene rearrangement in relation to radiation dosage.J. Genet. 37, pt. 3 abst.

    Google Scholar 

  • Newcombe, H. B. (1941). The action of X-rays on chromosomes. I. The internal variable.J. Genet. (in the Press).

  • Rick, C. M. (1940). On the nature of X-ray induced deletions inTradescantia chromosomes.Genetics,25, 466–82.

    PubMed  CAS  Google Scholar 

  • Sax, K. (1938). Chromosome aberrations induced by X-rays.Genetics,23, 494–516.

    PubMed  CAS  Google Scholar 

  • —— (1939). The time factor in X-ray production of chromosome aberrations.Proc. nat. Acad. Sci., Wash.,5, 225–33.

    Article  Google Scholar 

  • —— (1940). Analysis of X-ray induced chromosomal aberrations inTradescantia.Genetics,25, 41–68.

    PubMed  CAS  Google Scholar 

Download references

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Authors and Affiliations

  1. John Innes Horticultural Institution, Merton, London

    Howard B. Newcombe (1851 Science Research Fellow)

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  1. Howard B. Newcombe
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Newcombe, H.B. The action of X-rays on the cell. Journ. of Genetics 43, 237–248 (1942). https://doi.org/10.1007/BF02982756

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  • DOI: https://doi.org/10.1007/BF02982756

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