Meitoic crossing-over between the X and Y chromosomes of male mice carrying the sex-reversing (Sxr) factor


In the mouse, as in many other species, the X and Y chromosomes are seen to pair end-to-end at diakinesis1, which has led to speculation as to whether chiasmata and crossing-over occur earlier in meiosis1. Arguments in favour of this have recently been presented2–4, but because of the absence of appropriate genetic and cytological markers little clear-cut evidence has been obtained. Studies with ‘sex-reversed’ (Sxr) mice5 carried out earlier this year6 have suggested that the transfer of chromatin from the Y to the X chromosome takes place during meiosis, but in this instance the interpretation was confused by the claim that X/Y Sxr mice possess two Y chromosomes, contrary to earlier reports7. We present evidence here that: (1) X/Y Sxr mice have a single abnormal Y chromosome possessing an additional dark-staining distal body; (2) during meiosis, this body is transferred by crossing-over from one chromatid of the Y to one chromatid of the X. Furthermore, closer inspection of XY bivalents in mice not carrying Sxr suggests that crossing-over is a normal feature of X–Y pairing, and may be a necessary requirement for the production of functional sperm. Details of the mode of inheritance of Sxr are given in Table 1.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Crewe, F. A. E. & Koller, P. C. J. Genet. 26, 359–383 (1932).

    Article  Google Scholar 

  2. 2

    Burgoyne, P. B. Hum. Genet. (in the press).

  3. 3

    Eicher, E. M. in Prospects for Sexing Mammalian Sperm (eds Amann, R. T. & Seidell, G. E.) (Colorado University Press, Boulder, 1982).

    Google Scholar 

  4. 4

    Hansmann, I. Cell 30, 331–332 (1982).

    CAS  Article  Google Scholar 

  5. 5

    Cattanach, B. M., Pollard, C. E. & Hawkes, S. G. Cytogenetics 10, 318–337 (1971).

    CAS  Article  Google Scholar 

  6. 6

    Singh, L. & Jones, K. W. Cell 28, 205–216 (1982).

    CAS  Article  Google Scholar 

  7. 7

    Lyon, M. F., Cattanach, B. M. & Charlton, H. M. in Mechanisms of Sex Differentiation in Mammals (eds Austin, C. R. & Edwards, R. G.) 329–386 (Academic, New York, 1981).

    Google Scholar 

  8. 8

    Chandley, A. C. & Fletcher, J. M. Chromosoma 81, 9–17 (1980).

    CAS  Article  Google Scholar 

  9. 9

    Evans, E. P., Burtenshaw, M. D. & Brown, B. B. Chromosoma 81, 19–26 (1980).

    CAS  Article  Google Scholar 

  10. 10

    Nesbitt, M. N. & Francke, V. Chromosoma 41, 145–158 (1973).

    CAS  Article  Google Scholar 

  11. 11

    Ford, C. E. Transplantation 4, 333–335 (1966).

    CAS  Article  Google Scholar 

  12. 12

    Moses, M. J. et al. J. Cell Biol. 79, 123a (1978).

    Google Scholar 

  13. 13

    Tres, L. L. J. Cell Sci. 25, 1–15 (1977).

    CAS  PubMed  PubMed Central  Google Scholar 

  14. 14

    Evans, E. P. & Phillips, R. J. S. Nature 256, 40–41 (1975).

    ADS  CAS  Article  Google Scholar 

  15. 15

    Fisher, G. & Lyon, M. F. Mouse News Lett. 64, 58 (1981).

    Google Scholar 

  16. 16

    Solari, A. G. Chromosoma 29, 217–236 (1970).

    CAS  Article  Google Scholar 

Download references

Author information



Rights and permissions

Reprints and Permissions

About this article

Cite this article

Evans, E., Burtenshaw, M. & Cattanach, B. Meitoic crossing-over between the X and Y chromosomes of male mice carrying the sex-reversing (Sxr) factor. Nature 300, 443–445 (1982).

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.