Histones are basic proteins that associate with DNA to form the nucleosome that is essential for the packaging of the genomic DNA into compact structures.
There are 5 types of histones namely H2A, H2B, H3, H4 and H1 linker histones.
Inside a nucleosome, they exist as two dimers of (H2A-H2B) and a complex of (H32-H42) ultimately forming an octamer.
H1 linker histone associates externally with the nucleosome and helps in further compaction of the chromatin structure.