). Euchromatin comprises the most active portion of the genome within the cell nucleus. Structure The structure of euchromatin is reminiscent of an unfolded set of beads along a string, wherein those beads represent nucleosomes. Nucleosomes consist of eight proteins known as histones, with approximately 147 base pairs of DNA wound around them; in euchromatin, this wrapping is loose so that the raw DNA may be accessed. Each core histone possesses a `tail' structure, which can vary in several ways… (More on Euchromatin)