The genomes of most eukaryotes are larger and more complex than those of prokaryotes. The presence of large amounts of noncoding sequences is a general property of the genomes of complex eukaryotes. In eukaryotic cells, DNA packaging is more complicated because they contain an amount of DNA that is much larger than that of prokaryotic cells. So eukaryotic cells which have complex chromosomes are composed of DNA-histone proteins. But in prokaryotic cells, histones are absent.