chromatin /krō″mətin/ [Gk, chroma, color] , the material within a cell nucleus from which the chromosomes are formed. It consists of fine, threadlike strands of DNA attached to proteins called histones and is readily stained with basic dyes. Chromatin occurs in two forms, euchromatin and heterochromatin, which are distinguishable during the phases of the cell cycle by their different degrees of staining, which in turn depends how tightly they are coiled. During cell division, portions of the chromatin condense and coil to form the chromosomes. Also called chromoplasm, karyotin. See also chromatid, euchromatin, heterochromatin, sex chromatin. −chromatinic, adj.
