Practice question

Chromatosome differs from nucleosome core particle by retention of linker histone H1 and extra protected DNA length. Core particle with octamer protects 147 base pairs, but complete chromatosome containing H1 protects additional twenty base pairs, ten on each side beyond core entry, totaling 167 base pairs. Measurement obtained by micrococcal nuclease digestion followed by DNA sequencing of protected fragments when H1 retained; extensive digestion removes H1 reducing fragment to 147 base pairs core. Universally reported value 167 base pairs defines functional unit before 30 nanometer fiber formation in vitro and in vivo.