Abstract
Bands have been observed in the fixed mitotic chromosomes of Mus musculus L cell with no further treatment. These bands, which are very similar to G bands, can be seen by phase contrast microscopy, ultraviolet microscopy and Gold/Palladium shadowing. This indicates that the cause of banding is a differential distribution of chromatin. Alterations in chromatin morphology can be induced by post fixation treatments of the fixed chromosome. A model is constructed on this evidence which unifies the apparent variety in the techniques which are thought to induce G bands and explains the action of Giemsa stain. It is concluded that these treatments act by promoting the disruption of chromatin structure which is then reformed in the presence of the Giemsa stain, the Azure-B component of the stain acting in a manner similar to divalent cations. A new technique for inducing C bands is reported. The denaturation and differential reassociation of DNA is not a suitable explanation of the mechanism of this technique. The hypothesis put forward here, explaining G bands, also explains the induction of C bands as a result of a differential destruction of chromatin morphology. The differential distribution of chromatin that gives G bands is thought to be disrupted by a technique that maintains the more resistant morphology of the centromeric heterochromatin, C bands.
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Arrighi, F. E., Hsu, T. C.: Localisation of heterochromatin in human chromosomes. Cytogenetics 10, 81–88 (1971)
Barnett, R. I., MacKinnon, E. A., Romera-Sierra, C.: Delineation of human chromosomes contour by heat treatment and haemotoxylin staining. Chromosoma (Berl.) 40, 299–306 (1973)
Caspersson, T., Farber, S., Foley, G. E., Kudynowski, J., Modest, E. J., Simonsson, E., Wagh, U., Zech, L.: Chemical differentiation along metaphase chromosomes. Exp. Cell Res. 49, 219–222 (1968)
Comings, D. E., Avelino, E., Okada, T. A., Wyandt, A. E.: The mechanism of C and G banding of chromosomes. Exp. Cell Res 77, 469–493 (1973)
Dick, C., Johns, E. W.: The effect of two acetic acid containing fixatives on the histone content of calf thymus deoxyribonucleoprotein and calf thymus tissue. Exp. Cell Res. 51, 626–636 (1968)
Dutrillaux, B., Lejeune, J.: Cytogénétique humaine — Sur un nouvelle technique d'analyse du caryotype humain. C. R. Acad. Sci. (Paris) 272 D, 2638–2640 (1971)
Gormley, I. P., Ross, Q.: Surface topography of human chromosomes. Exp. Cell Res. 74, 585–589 (1972)
Grouchy, J. de, Fianz, C., Lejeune, J.: Cytogénétique humaine — mise en évidence de la structure fine des chromosomes humaines par digestion enzymatique (pronase en particulier). C. R. Acad. Sci. (Paris) 273, 587–588 (1971)
Gurr, E.: The rational use of dyes in biology, p. 359, London: Leonary Hill 1965
Hungerford, D. A., Ashton, F. T., Balban, G. B., La Badie, G. U., Messatzzia, L. R., Haller, C., Miller, A. B.: The C group pachytene bivalent with a locus characteristic for parachromosomally situated particulate bodies (parameres). A provisional map in human males. Proc. nat. Acad. Sci. (Wash.) 69, 2165–2168 (1972)
Kato, H., Moriwaki, K.: Factors involved in the production of banded structures in mammalian chromosomes. Chromosoma (Berl.) 38, 105–120 (1972)
Kato, H., Yosida, T. H.: Banding patterns of Chinese hamster chromosomes revealed by new techniques. Chromosoma (Berl.) 36, 272–280 (1972)
Lee, C. L. Y., Welch, J. P., Lee, S. H. S.: Banding of human chromosomes by protein denaturation. Nature (Lond.) New Biol. 241, 142–143 (1973)
Lezzi, M.: Differential gene activation in isolated chromosomes. Int. Rev. Cytol. 29, 127–168 (1970)
Ohnuki, Y.: Morphological studies of the spiral structure of human somatic chromosomes. Chromosoma (Berl.) 25, 402–428 (1968)
Pardue, M. L., Gall, J. G.: Chromosomal localisation of mouse satellite DNA. Science 168, 1356–1358 (1970)
Paris Conference 1971: Standardisation in human cytogenetics. Cytogenetics 11, 313–456 (1972)
Robert, M.: Effect of ionic strength and pH on the differential decondensation of nucleoproteins in isolated salivary gland nuclei and chromosomes of Chironomus thummi. Chromosoma (Berl.) 36, 1–33 (1971)
Seabright, M.: The use of proteolytic enzymes for the mapping of structural rearrangements in the chromosomes of man. Chromosoma (Berl.) 36, 204–210 (1972)
Solari, A. J.: The ultrastructure of chromatin fibres. Exp. Cell Res. 53, 553–336 (1968)
Solari, A. J.: The ultrastructure and composition of the synaptonemal complex in spread and negatively stained spermatocytes of the golden hamster and albino rat. Chromosoma (Berl.) 39, 237–263 (1972)
Stubblefield, E.: The structure of mammalian chromosomes. Int. Rev. Cytol. (in press, 1973)
Sumner, A. T.: A simple technique for demonstrating centromeric heterochromatin. Exp. Cell Res. 75, 304–306 (1972)
Sumner, A. T., Evans, H. J., Buckland, R. A.: New technique for distinguishing between human chromosomes. Nature (Lond.) New Biol. 232, 204–210 (1972)
Takagi, N, Oshimura, M.: Fluorescence and Giemsa banding studies of the allocyclic × chromosome in embryonic and adult mouse cells. Exp. Cell Res. 78, 127–135 (1973)
Utakoji, T.: Differential staining of human chromosomes stained with potassium permanganate. Nature (Lond.) 239, 168–170 (1972)
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McKay, R.D.G. The mechanism of G and C banding in mammalian metaphase chromosomes. Chromosoma 44, 1–14 (1973). https://doi.org/10.1007/BF00372569
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DOI: https://doi.org/10.1007/BF00372569