Histones are highly conserved proteins that serve as the structural scaffold for the organization of nuclear DNA into chromatin. The four core histones, H2A, H2B, H3, and H4, assemble into an octamer (2 molecules of each). Subsequently, 146 base pairs of DNA are wrapped around the octamer, forming a nucleosome. The linker histone, H1, interacts with linker DNA between nucleosomes and functions in the compaction of chromatin into 30nm chromatin fibers and higher order structures.