DNA compaction and histones. Illustration of a stage in the compaction of DNA (deoxyribonucleic acid). The DNA strand coils around proteins called histones (pink). This forms circular structures called nucleosomes (five shown here). These histones have 'tails' sticking out for modification by attracting other proteins to attach to them. Further coiling (not shown) forms strands of chromatin, which condenses during cell division to form structures called chromosomes.