=====Histone=====
Histones are highly alkaline [[protein]]s found in eukaryotic cell nuclei that package and order the DNA into structural units called [[nucleosome]]s.

They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long (a length to width ratio of more than 10 million to 1 in human DNA). For example, each human cell has about 1.8 meters of DNA, (~6 ft) but wound on the histones it has about 90 micrometers (0.09 mm) of chromatin, which, when duplicated and condensed during mitosis, result in about 120 micrometers of chromosomes.

Alterations in [[enzyme]]s that are "writers," "erasers," or "readers" of [[histone]] modification marks are common.

see [[Histone deacetylase]].

see [[Histone methylation]].