IAP and Line1 DNA methylation profiles in blastocysts. Sodium bisulfite sequencing was used to examine the DNA methylation patterns of (A) IAP LTR and (B) Line1 5′ end sequences in blastocyst DNA. Blastocysts were obtained from control, low- and high-dose hormone treatment groups. Target sequences were amplified, cloned and sequenced. Open circles, unmethylated CpGs; black circles, methylated CpGs; gray circles, not analyzable/mutated CpG site. Each row represents an individual sequenced clone. Only black and white circles were analyzed. The percentage of methylated CpGs (black circles/(black + white circles)) is indicated.