what is satellite dna in a genome?explain their role in dna finger printing?

Satellite DNA consists of highly repetitive DNA with very high frequency of adenine & thymine, this distinctive base composition of simple sequence DNA makes differences in buoyant density; result in the formation of satellite to the main DNA band when separated by CsCl density gradient centrifugation. The sequence of these DNA is known as satellite DNA. Satellite DNAs are species specific. Minisatellites and microsatellites are tandemly repeated DNA and also classed as satellite DNA.

The size of a Minisatellites ranges from 1 kb to 20 kb.  One type of Minisatellites is called variable number of tandem repeats (VNTR).  Its repeat unit ranges from 9 bp - 80 bp.  They are located in non-coding regions.  The number of repeats for a given minisatellite differs between individuals.  This feature is the basis of of DNA fingerprinting.