ABSTRACT
In the indirect mass isolation technique, the general stages include the disintegration of the cytoplasm through mechanical or chemical means, keeping the nucleus intact, followed by filtration through mesh or cheesecloth, differential centrifugation in suitable liquids and sedimentation. For polytene nuclei of Drosophila, several methods have been proposed including even mass isolation as they provide ideal materials for the study of gene action. Individual chromosome isolation through micromanipulation is well suited for preparation of chromosome specific DNA library through cloning and amplification. For chromosome isolation, metaphase cell populations treated with colcemid are cooled at 4 °C in fresh medium to inactivate trypsin, dissolve mitotic apparatus and remove residual colcemid. After chromosome isolation, the initial step for the analysis of components is the separation of DNA and protein, and then histone and nonhistone moieties.
