Euchromatin is a lightly packed form of chromatin that's rich in gene concentration, and is often (but not always) under active transcription. Unlike heterochromatin, it's found in both eukaryotes and prokaryotes. Structure The structure of euchromatin is reminiscient of an unfolded set of beads along a string, where those beads represent nucleosomes. Nucleosomes consist of eight proteins known as histones, with approximately 146 base pairs of DNA wound around them; in euchromatin this wrapping… (More on Euchromatin)