Chromocentres in polymorphs as interphase markers for chromosomes having increased constitutive heterochromatin.

After staining with the BSG technique for constitutive heterochromatin, human polymorphs exhibit chromocentres which are presumably derived from these chromosomal regions. In five individuals having an extended centromeric heterochromatin region on one No. 1 chromosome, a particularly large chromocentre was seen in the majority of polymorphs. Thus, prominent chromocentres in polymorphs may indicate the presence of constitutive heterochromatin variants.