Alpha satellite DNA is

      Composed of highly repetitive sequence elements found near human chromosome centromeres, and in most cases is chromosome-specific.

      Used to determine aneuploidy and,

      To identify the origin of small "marker" chromosomes

A dicentric marker chromosome was discovered to be derived from #14 or #22 as the results of this mixture of alpha satellites shows. The marker is indicated by the arrow. Notice the double signal, because of the presence of two centromeres.

Further information:

http://www.slh.wisc.edu/cytogenetics/procedures/fish/index.php