1. Repeating units of organisation of chromatin fibres in chromosomes, consisting of around 200 base pairs and two molecules each of the histones H2A, H2B, H3 and H4. most of the DNA (around 140 base pairs) is believed to be wound around a core formed by the histones, the remainder joins adjacent nucleosomes, thus forming a structure reminiscent of a string of beads.
Origin: Gr. Soma = body
This entry appears with permission from the Dictionary of Cell and Molecular Biology
(11 Mar 2008)
