Analysis of DNase1 hypersensitive sites along the −^ZF chromosome.

DNA from the nuclei of an interspecific MEL hybrid containing the α−^ZF chromosome (ZF8) or a normal chromosome (JY5-4) using probes and enzymes that detect the hypersensitive sites at the CpG islands associated with the α2-globin promoter (H) and the surrounding CpG islands B, G, E, and K (see Figure1). Analysis of HSs at E and H in normal hybrids (JY5-4) and abnormal hybrids (ZF8) shows that although the constitutive site at E is sensitive in both, the HS at the silenced α promoter is insensitive.