Heterochromatic regions of the eukaryotic genome harbour DNA sequences that are repeated many times in tandem, collectively known as satellite DNAs. Different satellite sequences co-exist in the genome, thus forming a set called a satellite DNA library. Within a library, satellite DNAs represent independent evolutionary units. Their evolution can be explained as a result of change in two parameters: copy number and nucleotide sequence, both of them ruled by the same mechanisms of concerted evolution. Individual change in either of these two parameters as well as their simultaneous evolution can lead to the genesis of species-specific satellite profiles. In some cases, changes in satellite DNA profiles can be correlated with chromosomal evolution and could possibly influence the evolution of species.