nucleosome 1 topic · 1 source Science› Biotechnology and GeneticsFood BiotechnologySpherical sub-units of eukaryotic chromatin that are composed of a core particle consisting of an octamer of histones (two molecules each of histones H2a, H2b, H3 and H4) and 146 bp of DNA.UN Food and Agriculture Organization — Glossary of Biotechnology for Food and Agriculture Cite