Satellite chromosome

Besides the centromere, one or more secondary constrictions can also be observed in some chromosomes at metaphase. The secondary constrictions are always constant in their positions and hence can be used as markers that identify particular chromosomes. A satellite chromosome or SAT chromosome has a chromosome segment that is separated from the main body of the chromosome by such a secondary constriction. The term is due to Sergei Navashin, in 1912.