Figure 6.
Structure of the CpG island in the first intron of Impact. Tandem repeated structures are schematized by broad arrows (A). The island contains two units designated as 1 and 2, the nucleotide sequences of which are shown in B and C, respectively. Although many polymorphic sites are found between the two mouse strains, two HhaI sites and three HpaII sites are conserved and indicated in the figure. These sites were thus used for the methylation-specific PCR assay in Fig. 7.
