Core particles are connected by stretches of linker DNA, which can be up to about 80 bp long. Technically, a nucleosome is defined as the core particle plus one of these linker regions; however the word is often synonymous with the core particle. Genome-wide nucleosome positioning maps are now available for many model organisms and human cells.

Linker histones such as H1 and its isoforms are involved in chromatin compaction and sit at the base of the nucleosome near