Mosaicism in maternal allele-specific methylation. (A) Maternal allele-specific methylation of CGI #59. Direct sequencing was performed using the PCR products from mock-treated (bottom left), HhaI- (bottom center), and McrBC-digested (bottom right) DNA isolated from PBLs. The arrowhead indicatesthe A/C SNP site. Note that the maternally inherited A allele wasdetected from both Hha I-treated (or methylated) DNA and McrBC-treated (or unmethylated) DNA. (B) Bisulfite genomic sequencing of CGI #59. 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 A/C SNP site is also indicated. Note that the clonesfor the maternally inherited A allele are composed of two populations, one completely methylated and the other completely escaping methylation.
