a, mRNA expression levels in d10 and GV oocytes of the genes associated with methylated CGIs, either promoter (red, n=410) or intragenic (blue, n=555). b, Methylation levels in blastocysts of the CGIs identified as methylated in mature oocytes; twelve known germline DMRs with informative coverage are displayed in red (range 45.2%-58.7%). c, Range of methylation in blastocysts of the CGIs methylated specifically in oocytes (n=803) or sperm (n=51), methylated in both oocytes and sperm (n=86) and unmethylated in gametes (n=11512). d, Bisulphite sequencing in GV oocytes, sperm and C57BL/6JxCAST/Ei hybrid E3.5 blastocysts of the Syt2 CGI. Bisulphite sequence profiles from the maternal (mat) and paternal (pat) alleles in blastocysts were discriminated by polymorphisms between C57BL/6J and CAST/Ei. Open circles represent unmethylated CpGs and filled circles methylated CpGs.