Relative mRNA expression of parental genes in the Dlk1-Dio3 region. (A) Expression of paternal genes was significantly higher in human fertilized embryonic stem cells. Dlk1-Dio3 genes in BGHPES-1 were expressed at significantly higher levels, compared to BGHPES-2. (B) Maternally expressed genes were significantly up-regulated with no significant differences in both BGHPES-1 and -2, compared with human fertilized embryonic stem cells. Different letters indicate significant differences among data (P <0.05) while the same letters imply no differences (P >0.05).