The constitutive heterochromatin of porcine chromosomes

: The constitutive heterochromatin of porcine chromosomes was cytologically resolved into four types by using a combination of both C-banding techniques and base specific DNA binding fluorochromes. The four types of constitutive heterochromatin are: 1) C-band positive, A-T rich heterochromatin located in the centromeric region of acrocentric chromosomes; 2) faint C-band positive, G-C rich heterochromatin located in the centromeric region of biarm chromosomes; 3) C-band positive heterochromatin located in the long arm of the Y chromosome lacking available binding sites for either A-T or G-C specific fluorochromes; and 4) C-banding negative centromeric heterochromatin of the Y chromosome lacking available binding sites for either A-T or G-C specific fluorochromes.