Evidence Indicating that the X and the Y or the Z and the W were Originally an Homologous Pair of Ordinary Chromosomes

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


Today, the X and Y of mammals and the Z and W of birds are totally different from each other in size as well as genetic content. Yet, it can be shown that the two were originally an homologous pair of ordinary chromosomes or autosomes. A broad review of the sex-determining mechanism of various vertebrates enables us to reconstruct, step-by-step, this process of sex chromosome differentiation.


Lower Vertebrate Oryzias Latipes Female Heterogamety Gonochoristic Species Male Heterogamety 
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.


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Copyright information

© Springer-Verlag Berlin · Heidelberg 1966

Authors and Affiliations

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

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