The initial stage of packaging have the binding of the chromosomal DNA to histones.  Whole, in chromosomes the ratio of the DNA to histones on a weight basis is around 1:1. There are five main types of histones called as H1, H2A, H2B, H3 and H4. Histones  are very  basic  proteins;  about  25 percent  of their  amino acids  are  lysine  or  arginine  so  histones  have  a  vast  number  of  positively charged amino acid side-chains.  These positively charged groups therefore bind to the negatively charged phosphate groups of DNA.  Not surprisingly giving their importance in packaging DNA the amino acid series of histones have been highly conserved in evolutio.