Maternal allele-specific methylation pinpointed to tandem repeats. (A) Maternal allele-specific methylation of CGI #112. A map of CGI #112 (500 bp) isshown on the top with the positionsof A/T and C/T SNPs(i.e., SNP1 and SNP2). The arrowsin the map indicate the tandem repeats. The CGI wasPCR-amplified from untreated (bottom left), HhaI-digested (bottom center), and McrBC-digested (bottom right) genomic DNA isolated from PBLs of a C/T heterozygote at SNP2. The amplified productswere subjected to direct sequencing. The vertical arrowhead in each electropherogram denotes the SNP2 (C/T) sites. (B) Bisulfite genomic sequencing of CGI #112. Each row of circles corresponds to each clone of bisulfite PCR products. Open and closed circles stand for unmethylated and methylated C residues, respectively. The SNP1 (A/T) site is indicated by the arrowhead.
