The histone multigene family

Eukaryote chromosomes contain roughly equal amounts of DNA and protein. The proteins present are divided into two categories, histones and non-histone proteins. The former are small basic 

Eroteins, and in most cells there are five classes, nown as Hi, H2a, H2b, H3 and H4 (Table 9.4), although a sixth class, H5, is found in nucleated erythrocytes of certain vertebrates (see Section 9.5.2.). Each class from one species generally comprises less than ten different proteins, and in some cases only a single protein. By contrast, the non-histone 

Histone Function Rate of evolution No. of genes for each type in domestic fowl Expression 

HI Holds ends of nucleosomal 12 6 S-phase of cell cycle 

---