19.1 Introduction Histones are conserved dNa-binding proteins of eukaryotes that form the nucleosome. the basic subunit of chromatin Nucleosome is the basic structural subunit of chromatin, consisting of 200 bp of dna and an octamer of histone proteins 消当Histones are conserved DNA-binding proteins of eukaryotes that form the nucleosome, the basic subunit of chromatin. Nucleosome is the basic structural subunit of chromatin, consisting of ~200 bp of DNA and an octamer of histone proteins. 19.1 Introduction