It shows repetitive sequences of genes
Besides centromere, secondary constriction can also be observed in some chromosomes, which if present in the distal region of the arm, would pinch off a small fragment called Satellite.
The satellite remains attached to the rest of the body of chromosomes by a thread of chromatin. The secondary constrictions are always constant in their positions and hence can be used as markers. The chromosomes having a satellite are marker chromosomes and are also called SAT chromosomes.