In prokaryotes, centrifugation of fragmented DNA on a CsCl gradient produces a single band at a given density, irrespective of the size of the fragments. (DNA density will increase with increasing percentage of G:C)
In prokaryotes, always got a single band.
In eukaryotes, the same experiment lead to 2 bands: the main density band and satellite band
Eukaryotes have satellite DNA
Satellite DNA consists of very large arrays of tandemly repeating, non-coding DNA. Satellite DNA is the main component of functional centromeres