Zeitschrift für Parasitenkunde

, Volume 46, Issue 4, pp 291–295 | Cite as

Morphology and behaviour of sex chromosomes during meiosis in Ascaris suum

  • T. Mutafova


The morphology and behaviour of sex chromosomes was studied in A. suum during meiosis. It was found that the five sex chromosomes have their proper characteristic. The largest is submetacentric, of 2 microns mean length. The second largest is acrocentric, mean length of 1.4 μ. The third largest is metacentric, 1.2 μ mean length. The fourth and the fifth are metacentric, of mean length of 1 μ.

In primary and secondary spermatocyte cells the sex chromosomes are close to each other, most often in the peripheral part of the cell. During anaphase I the pentad sex chromosomes lie freely between the two sister cells. It is assumed that in anaphase II the five sex chromosomes divide equally and are regularly distributed in the daughter cells.

It was found that the chromosomes set of female Ascaris in metaphase I contains 24 bivalent chromosomes n=24 and of male Ascaris 19 bivalents and 5 univalents.

It is assumed that the univalent chromosomes, found in spermatocyte cells, determine sex.


Ascaris Univalent Chromosome Sister Cell Primary Oocyte Bivalent Chromosome 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Eduards, C. L.: The idiochromosomes in Ascaris megalocephala and Ascaris lumbricoides. Arch. Zellforsch. 5 (1910)Google Scholar
  2. Goodrich, H. B.: The germ cells in Ascaris incurva. J. exp. Zool. 21, 61–98 (1916)CrossRefGoogle Scholar
  3. Jeffry, E. C., Edwin, J. H.: The nature of certain so- called sex chromosomes in Ascaris. Cellule 46, 237–244 (1938)Google Scholar
  4. Vassilev, I., Mutafova, T.: Comparative studies on the karyotype of Ascaris suum and “Ascaris ovis” Z. Parasitenk. 43, 115–121 (1974)CrossRefGoogle Scholar
  5. Walton, A. C.: Ascaris canis (Werner) and Ascaris felis (Göze) a taxonomic and cytological comparison. Biol. Bull. 31, 364–371 (1916)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • T. Mutafova
    • 1
  1. 1.Central Laboratory of HelminthologyBulgarian Academy of SciencesSofiaBulgaria

Personalised recommendations