Structural Analysis of Polytene Chromosome Bands and Interbands

Photodensitometric studies on the electron microscopic negatives of thin‐sectioned salivary gland chromosomes of Drosophila melanogaster were carried out for estimating the cross sectional area of chromatin in interbands and bands. Comparison of results obtained from 26 exactly identified pairs of interbands and bands in Bridges' subdivisions 22E‐F, 26C, 26F and 31B‐D of 2L indicate that the proportion of chromatin volume in equal area of interband is only ca. 2.43 % of the volume of band chromatin in thin‐sections of fixed and stained polytene chromosomes. The cross section areas of interband and band chromatin in equal areas of EM negative were estimated by determining the average density for the 5‐nm interband fibril and for the 12‐nm band fiber and by comparing the density and dimensions of these unit fibers to the density and dimensions of interband and band chromatin. Because the axial length of interbands is on average twice the axial length of bands, the relative volume of interband chromatin is ca. 4.9 % of the total volume of chromatin in the salivary gland chromosomes.

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Structural Analysis of Polytene Chromosome Bands and Interbands

Cited by 4 publications

References 21 publications

Electron Microscopic Mapping and Ultrastructure of Drosophila Polytene Chromosomes

Electron Microscopic Mapping and Ultrastructure of Drosophila Polytene Chromosomes

Electron microscopic band-interband pattern of the X chromosome in Drosophila hydei

Volume of chromatin fibers in interbands and bands of polytene chromosomes

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