Summary
The crossDrosophila insularis ×Drosophila tropicalis produces viable but completely sterile hybrids. Chromosomes have been studied in the cells of the salivary glands in hybrid larvae. The euchromatic sections of the chromosomes of the two species remain completely unpaired in the hybrid, despite the obvious similarities of the disc patterns in many portions of these chromosomes. A common chromocenter is nevertheless formed, owing to a mutual attraction of the heterochromatic sections adjacent to the centromeres in all the chromosomes. The condition of the chromosomes in the female and male cells is represented schematically in Fig. 1. The X-chromosomes show a remarkable difference in behavior in the cells of the two sexes. The euchromatic strands representing the X-chromosome are appreciably greater in width but somewhat paler in staining in male than in female larvae. This is a visible counterpart of the genetic phenomenon of dosage compensation.
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The work reported in this article has been supported in part under Contract No. AT-(30-1)-1151, U. S. Atomic Energy Commission
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Dobzhansky, T. The X-chromosome in the larval salivary glands of hybrids Drosophila insularis × Drosophila tropicalis. Chromosoma 8, 691–698 (1956). https://doi.org/10.1007/BF01259527
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DOI: https://doi.org/10.1007/BF01259527