Abstract
DNA replication in the neo-X neo-Y sex determining system was studied by means of tritiated thymidine and autoradiography. Asynchronous replication was found in the X arm of the neo-X and the long arm of the neo-Y. In addition, striking asynchrony was also found for short isopycnotic homologous regions at the distal end of the autosmal arm of neo-X and the short arm of neo-Y to which pairing during meiosis is restricted. These short regions are asynchronous with respect to the heterochromatic segments as well as to the remaining proximal region of the autosomal euchromatic arm of neo-X. This difference in replication pattern within the same chromosome arm may be related to a differentiation between regions which are homozygous in both sexes and regions which are hemizygous in males.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Literature
Lima De Faria, A.: Incorporation of tritiated thymidine into meiotic chromosomes. Science 130, 503–504 (1959).
—: Differential uptake of tritiated thymidine into hetero- and euchromatin in Melanoplus and Secale. J. biophys. and biochem. Cytol. 6, 457–466 (1959).
—: Initiation of DNA synthesis at specific segments in the meiotic chromosomes of Melanoplus. Hereditas (Lund) 47, 674–694 (1961).
Mesa, A.: Cariologia de Dichroplus bergi. Rev. Agric. Piracicaba (Brasil) 37, 41–49 (1962).
Saez, F. A.: Gradient of heterochromatinization in the evolution of the sexual system neo-X neo-Y. Port. Acta Biol., Ser. A 6, 111–138 (1963).
—, and A. Vdiaz: Neo-X neo-Y system of sex determination in Xyleus laevipes (Orthoptera: Romaleinae). Texas Rep. Biol. Med. 18, 116–128 (1960).
Taylor, J. H.: Distribution of tritium labelled DNA among chromosomes during meiosis, spermatogenesis in the grasshopper. J. Cell Biol. 25, 57–67 (1965).
White, M. J. D.: Animal cytology and evolution. 2nd. ed. Cambridge, England: University Press 1954.
Author information
Authors and Affiliations
Additional information
This work was supported by U.S. Atomic Energy Commission Contract N AT (30-1) 3517 to Prof. F. A. Saez.
Rights and permissions
About this article
Cite this article
Diaz, M.O., Saez, F.A. DNA synthesis in the neo-X neo-Y sex determination system of Dichroplus bergi (Orthoptera: Acrididae). Chromosoma 24, 10–16 (1968). https://doi.org/10.1007/BF00329603
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00329603