Intraspecific hybridisation and the release of mutator activity


IT has been suggested by Grant1–2 that mutation and hybridisation may not be independent of one another as sources of genetic variation in natural populations. Indeed, it has been shown in both plants and animals3–8 that hybridisation can stimulate the production of new mutations and chromosome breakage events. The possible role of intraspecific hydridisation in inducing genetic change has recently been discussed in various contexts, especially in relation to the action of mutator genes in natural populations1,2,9–11. We have previously suggested that mutator factors, which are known to induce both visible and lethal mutations and chromosome breakage, are commonly present in natural populations of Drosophila melanogaster. Within sub-populations, however, these mutators are genetically suppressed. On hybridisation between subpopulations, genetic suppression breaks down, resulting in the release of mutator activity and, hence, in an explosive increase in genetic variation. Clearly, these explosions of mutation, which have been documented in some natural populations12,13, might have an important role in evolution and speciation. Here, we test this hypothesis of ‘hybrid release’ directly by determining whether intraspecific hybridisation increases the frequency of mutation above that found in the sampled natural population. Our study differs significantly from other assays of mutator gene effect14–16 in that mutation frequencies before and after hybridisation are compared directly. The results show that hybrid release of mutator activity does occur as the result of hybridisation, producing a severalfold increase in the frequency of mutation. Thus, hybrid release may be a major mechanism in the induction of genetic variation in natural populations and so may be a driving force in evolution.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Grant, V. The Origin of Adaptations (Columbia University Press, 1963).

  2. 2

    Grant, V., Plant Speciation (Columbia University Press, 1971).

  3. 3

    Mangelsdorf, P. C. Cold Spring Harb. Symp. quant. Biol. 23, 409–421 (1958).

  4. 4

    Lewis, H. Evolution 16, 257–271 (1962).

  5. 5

    Lewis, H. & Raven, P. H. Evolution 12, 319–336 (1958).

  6. 6

    Sturtevant, A. H. Proc. natn. Acad. Sci. U.S.A. 25, 308–310 (1939).

  7. 7

    Newman, L. J. Genetics 53, 55–63 (1966).

  8. 8

    Robertson, D. S. Mutat. Res. 51, 21–28 (1978).

  9. 9

    Thompson, J. N. Jr & Woodruff, R. C. Nature 274, 317–321 (1978).

  10. 10

    Sturtevant, A. H. Q. Rev. Biol. 12, 464–467 (1937).

  11. 11

    Ives, P. T. Evolution 4, 236–252 (1950).

  12. 12

    Spencer, W. P. Am. Nat. 69, 223–238 (1935).

  13. 13

    Berg, R. L. Symp. on the Mutation Process, Prague (1965).

  14. 14

    Slatko, B. E. & Hiraizumi, Y. Genetics 75, 643–649 (1973).

  15. 15

    Yamaguchi, O. Mutat. Res. 34, 389–406 (1976).

  16. 16

    Kidwell, M. G., Kidwell, J. F. & Ives, P. T. Mutat. Res. 42, 89–98 (1977).

  17. 17

    Woodruff, R. C. & Thompson, J. N. Jr Heredity 38, 291–307 (1977).

  18. 18

    Henderson, S. A., Woodruff, R. C. & Thompson, J. N. Jr Genetics 88, 93–107 (1978).

  19. 19

    Lindsley, D. L. & Grell, E. H. Carnegie Institute of Washington, Publ. No. 627 (1968).

  20. 20

    Golubovsky, M. D., Ivanov, Yu. N. & Green, M. M. Proc. natn. Acad. Sci. U.S.A. 74, 2973–2975 (1977).

  21. 21

    Green, M. M. Proc. natn. Acad. Sci. U.S.A. 74, 3490–3493 (1977).

  22. 22

    Lewis, H. Science 152, 167–172 (1966).

Download references

Author information



Rights and permissions

Reprints and Permissions

About this article

Cite this article

WOODRUFF, R., LYMAN, R. & THOMPSON, J. Intraspecific hybridisation and the release of mutator activity. Nature 278, 277–279 (1979).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.