plasmids are, like eukaryotic DNA, generally supercoiled . The DNA must first be released into its relaxed state for access for transcription , regulation, and replication . external image 1180px-Chromatin_Structures.png external image magnify-clip.png Fig. 2: The major structures in DNA compaction; DNA , the nucleosome , the 10nm "beads-on-a-string" fibre, the