Abstract
In the field vole, Microtus agrestis, most of the constitutive heterochromatin is localized in the giant chromosomes. A detailed examination of a large number of adult cell types reveals that this chromatin is actually present as a heterochromatic fiber in all interphase nuclei. Depending upon the cell types, however, the fiber shows varying degrees of condensation and folding ranging from a very long and extended fiber to a large compact chromocenter. The number of cell types with giant chromocenters was less commonly observed than those with extended fibers. This explains why some cells were previously thought to be devoid of heterochromatin.—The results of this investigation strongly indicate that constitutive heterochromatin represents a unique nuclear entity.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Arrighi, F. E., Hsu, T. C., Saunders, P., Saunders, G. F.: Localization of repetitive DNA in the chromosomes of Microtus agrestis by means of in situ hybridization. Chromosoma (Berl.) 32, 224–236 (1971).
Barr, M. L.: Sex chromatin techniques. In: Human chromosome methodology (J. J. Yunis, ed.), p. 1–16. New York: Academic Press 1965.
Flamm, W. G., Walker, P. M. B., McCallum, M.: Some properties of the single strands isolated from the DNA of the nuclear satellite of the mouse (Mus musculus). J. molec. Biol. 40, 423–443 (1969).
Leduc, E. H., Bernhard, W.: Recent modifications of the glycol methacrylate embedding procedure. J. Ultrastruct. Res. 19, 196–199 (1967).
Lee, J. C., Yunis, J. J.: A developmental study of constitutive heterochromatin in Microtus agrestis. Chromosoma (Berl.) 32, 237–250 (1971).
Nelson, R. D., Yunis, J. J.: Expression of constitutive heterochromatin in cultured fibroblasts from Microtus agrestis. Exp. Cell Res. 61, 457–461 (1970).
Pera, F.: Dauer der DNS-Reduplikation von Eu-und Heterochromatin bei Microtus agrestis. Chromosoma (Berl.) 25, 21–29 (1968).
Pflueger, O. H., Yunis, J. J.: Late replication patterns of chromosomal DNA in somatic tissues of the Chinese hamster. Exp. Cell Res. 44, 413–420 (1966).
Sachs, L.: The giant sex chromosomes in the mammal Microtus agrestis. Heredity 7, 226–237 (1953).
Schmid, W.: Heterochromatin in mammals. Arch. Klaus-Stift. Vererb.-Forsch. 42, 1–60 (1967).
— Smith, D. W., Theiler, K.: Chromatinmuster in verschiedenen Zelltypen und Lokalisation von Heterochromatin auf Metaphasechromosomen bei Microtus agrestis, Mesocricetus auratus, Cavia cobaya und beim Menschen. Arch. Klaus-Stift. Vererb.-Forsch. 40, 35–49 (1965).
Sieger, M., Pera, F., Schwarzacher, H. G.: Genetic inactivity of heterochromatin and heteropycnosis in Microtus agrestis. Chromosoma (Berl.) 29, 349–364 (1970).
Walker, P. M. B.: Origin of satellite DNA. Nature (Lond.) 229, 306–308 (1971).
Wolf, U., Flinspach, G., Böhm, R., Ohno, S.: DNS-Reduplikationsmuster bei den Riesen-Geschlechtschromosomen von Microtus agrestis. Chromosoma (Berl.) 16, 609–617 (1965).
Yasmineh, W. G., Yunis, J. J.: Satellite DNA in calf heterochromatin. Exp. Cell Res. 64, 41–48 (1971a).
—: Repetitive DNA of Microtus agrestis. Biochem. biophys. Res. Commun. 43, 580–587 (1971b).
Yunis, J. J., Roldan, L., Yasmineh, W. G., Lee, J. C.: Staining of satellite DNA in metaphase chromosomes. Nature (Lond.) 231, 532–533 (1971).
- Yasmineh, W. G.: Constitutive heterochromatin, repetitive DNA and cell function. Science (in press) 1971.
Author information
Authors and Affiliations
Additional information
This investigation was supported by NIH funds (Grant No. HD 1962).
Rights and permissions
About this article
Cite this article
Lee, J.C., Yunis, J.J. Cytological variations in the constitutive heterochromatin of Microtus agrestis . Chromosoma 35, 117–124 (1971). https://doi.org/10.1007/BF00285732
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00285732