Figure 4.

DNA is packaged into chromatin. About 80% of genomic DNA is packaged into nucleosomes, which consists of 146 base pairs of DNA wrapped around a histone octamer. The chromatin fibers adopt a “beads on a string” configuration with a diameter of 10 nm and may be further condensed into a compact 30 nm fiber. The chromatin is folded into a defined structure (as defined by the basic radial loop model) by chromatin remodeling enzymes during cell mitosis.