Constitutive heterochromatin (C-bands) in the centromeric region

The constitutive heterochromatin in the
centromeric region can be specifically stained
(C bands). The distal half of the long arm of the Y
chromosome is also C-band positive. The
centromeric heterochromatin in chromosomes
1, 9, and 16 and in the long arm of the Y chromosome
in humans is polymorphic. The lengths of
the heterochromatic segments in one or more
of these regions may vary among different individuals.