Not occurring in vertebrate sperm cells or bacteria, they are any group of water-soluble proteins found in conjunction with the DNA of chromosomes. Containing major parts of the basic amino acids argentine, histamine, lysine, they are thought to be involved in the condensation and coiling of chromosomes during cell division. They may also be involved in the suppression of gene activity, but in a non-specific way.
See Amino acids, Chromosome, DNA (deoxyribonucleic acid), Epigenetics, Eukaryote cell (or organism), Mitosis, Methylation, Nucleoid, Prokaryote cell (or organism), Regulator (or regulatory) gene, Spermatozoa