How Barbara McClintock discovered transposable elements in maize


The paper describes the early part of Barbara McClintock`s work on DNA transposons in maize, in which she discovered the Ac-Ds family of mobile "controlling elements". An account is first given of the cytology of the system that was used to generate intact chromosomes having "sticky" (broken) ends. Cytogenetical aspects of the chromatid and chromosome breakage-fusion-bridge cycles, deriving from breakage, are then described, which leads on to the way in which variegation in phenotypes of the maize kernels could be "read" in terms of chromosome breakage. The "genetic earthquake" event of 1944, triggered by introducing broken chromosomes into a zygote from both parents, lead to the discovery of Ds and Ac. Finding mobility of Ds from one chromosomal location to another was pure serendipity: the transposition showed itself while experiments were being undertaken to accurately map Ds. A similar chance observation revealed transposition of Ac as well, and then the relationship between the two elements was elucidated in terms of their autonomous and non-autonomous nature.

About the authors

- -


  1. Fedoroff N. V., 1983. Controlling elements in maize. In: Mobile Genetic Elements, Eds. James, A. Shapiro. Chapter 1. Academic Press, New York. P. 1–63.
  2. Fedoroff N. V., 1984.Transposable genetic elements in maize. Scientific American Vol. 250. P. 64–76.
  3. Fincham J. R. S., Sastry G. R. K., 1974. Controlling elements in maize. Ann Rev Genet. Vol. 8. P. 15–50.
  4. Jones R. N., 2005. McClintock’s controlling elements: the full story. Cytogenet. Genome Res. Vol. 109. P. 90–103.
  5. McClintock B., 1939. The behaviour in successive nuclear divisions of a chromosome broken at meiosis. Proc. Natl. acad. Sci. USA. Vol. 25. P. 405–416.
  6. McClintock B., 1941. The stability of broken ends of chromosomes in Zea mays. Genetics. Vol. 26. P. 234–282.
  7. McClintock B., 1942. The fusion of broken ends of chromosomes following nuclear fusion. Proc. natl. acad. sci. USA. Vol. 28. P. 458–463.
  8. McClintock B., 1951. Chromosome organization and gene expression. Cold Spring Harbor symp. quant. biol. Vol. 16. P. 13–47.
  9. McClintock B., 1956. Controlling elements and the gene. Cold Spring Harbor Symp. Quant. Biol. Vol. 21. P. 197–216.
  10. McClintock B., 1965. The control of gene action in maize. Brookhaven Symp. in Biol. Vol. 18. P. 162–184.
  11. McClintock B., 1978. Mechanisms that rapidly reorganize the genome. Stadler symp. Vol. 10. P.25–48. University of Missouri, Columbia.
  12. Rhoades M. M., 1945. On the genetic control of mutability in maize. Proc. Natl. Acad. Sci. USA. Vol. 31. P. 91–95.



Abstract - 579

PDF (Russian) - 234


Article Metrics

Metrics Loading ...



Copyright (c) 2012 - -.

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies