The Basic Difference in Constitution between the Mammalian X and the Drosophila X

  • Susumu Ohno
Part of the Monographs on Endocrinology book series (ENDOCRINOLOGY, volume 1)


During the course of evolution progressive genetic deterioration occurred to the Y-chromosome. As a result, the Y-chromosome of placental mammals became a highly specialized male-determiner, having but one function namely to induce the indifferent embryonic gonad to develop as testis. The consequence of this specialization by the Y was that almost all of the original Mendelian genes which had been maintained by the X-chromosome, had to accommodate themselves to a hemizygous existence in the heterogametic male sex. The hemizygous existence for all the genes on the X should be very perilous since monosomy for even the smallest autosome (only one-fourth the size of the X) is apparently lethal in man.


Interphase Nucleus Placental Mammal Dosage Compensation Meiotic Prophase Heterochromatic Region 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Barr, M. L., and L. F. Bertram: A morphological distinction between neurones of the male and female and the behavior of the nucleolar satellite during accelerated nucleoprotein synthesis. Nature 163, 676–677 (1949).PubMedCrossRefGoogle Scholar
  2. Galton, M., and S. F. Holt: Asynchronous replication of the mouse sex chromosomes. Exp. Cell Res. 37, 111–116 (1965).PubMedCrossRefGoogle Scholar
  3. German, J. L.: DNA synthesis in human chromosomes. Trans. N. Y. Acad. Sci. 24, 395–407 (1962).Google Scholar
  4. Gilbert, C. W., S. Muldal, L. G. Lajtha, and J. Rowley: Time-sequence of human chromosome duplication. Nature 195, 869–873 (1962).PubMedCrossRefGoogle Scholar
  5. Grumbach, M. M., and A. Morishima: Sex chromatin and the sex chromosomes: on the origin of sex chromatin from a single X-chromosome. Acta Cytol. 6, 46–60 (1962).PubMedGoogle Scholar
  6. Heitz, E.: Die somatische Heteropyknose bei Drosophila melanogaster und ihre genetische Bedeutung. Z. Zellforsch. Abt. Histochem. 20, 237–287 (1933).CrossRefGoogle Scholar
  7. Henking, H.: Untersuchungen über die ersten Entwicklungsvorgänge in den Eiern der Insekten. II. Über Spermatogenese und deren Beziehung zur Eientwicklung bei Pyrrhocoris apterus L. Z. wiss. Zool. 51, 685–736 (1891).Google Scholar
  8. Jagiello, G., and S. Ohno: Isopycnotic behavior of the X-univalent in the XO mouse ovum. Exp. Cell Res. 41, 459–462 (1966).PubMedCrossRefGoogle Scholar
  9. Junker, H.: Cytologische Untersuchungen an den Geschlechtsorganen der halbzwitterigen Steinfliege Perla marginata (Panzer). Arch. Zellforsch. 17, 185–259 (1923).Google Scholar
  10. Kaufmann, B. P.: Somatic mitoses of Drosophila melanogaster. J. Morphol. 56, 125–156 (1934).CrossRefGoogle Scholar
  11. Klinger, H. P.: The fine structure of the sex chromatin body. Exp. Cell Res. 14, 207–211 (1958).PubMedCrossRefGoogle Scholar
  12. Mcclung, C. E.: The spermatocyte divisions of the Locustidae. Kansas Univ. Sci. Bull. 1, 185–238 (1902).Google Scholar
  13. Muller, H. J.: Evidence of the precision of genetic adaptation. Harvey Lectures Ser. 43, 165–229 (1947–1948).Google Scholar
  14. Ohno, S., W. D. Kaplan, and R. Kinosita: On the end-to-end association of the X and Y-chromosomes of Mus musculus. Exp. Cell Res. 18, 282–290 (1959 a).Google Scholar
  15. Ohno, S., W. D. Kaplan, and R. Kinosita: Formation of the sex chromatin by a single X-chromosome in liver cells of Rattus norvegicus. Exp. Cell Res. 18, 415–418 (1959 b).Google Scholar
  16. Ohno, S., W. D. Kaplan, and R. Kinosita: X-chromosome behavior in germ and somatic cells of Rattus norvegicus. Exp. Cell Res. 22, 535–544 (1961).PubMedCrossRefGoogle Scholar
  17. Ohno, S., and T. S. Hauschka: Allocycly of the X-chromosome in tumors and normal tissues. Cancer Res. 20, 541–545 (1960).PubMedGoogle Scholar
  18. Ohno, S., and S. Making: The single X nature of the sex chromatin in man. Lancet I, 78–79 (1961).Google Scholar
  19. Taylor, J. H.: Asynchronous duplication of chromosomes in cultured cells of Chinese hamster. J. Biophys. Biochem. Cytol. 7, 455–464 (1960).PubMedCrossRefGoogle Scholar
  20. Tjio, J. H., and A. Levan: Notes on the sex chromosomes of the rat during male meiosis. Anales Estac. Exp. Aula Dei 4, 173–184 (1956).Google Scholar

Copyright information

© Springer-Verlag Berlin · Heidelberg 1966

Authors and Affiliations

  • Susumu Ohno
    • 1
  1. 1.Department of BiologyCity of Hope MedicalDuarteUSA

Personalised recommendations