Fig. 3.

Quantification of key genes expression in embryos cultured in vitro for 96 h. a Imprinted genes expression. b Proteinase genes expression. c MAPK signal pathway genes expression. d Superoxide dismutase genes expression. LFE and HFE, fertilized embryos cultured in 5% and 20% O₂ respectively; LPA and HPA, parthenogenetic embryos cultured in 5% and 20% O₂ respectively. Gene-expression data are determined by real-time PCR and normalized to the levels of β-actin mRNA, with the average value of LFE groups as controls set to one and compared across groups. Data are presented as mean ± SEM, with letters indicating differences between groups, a vs. b, p < 0.05; c vs. d, p < 0.001; c vs. e, p < 0.0001; d vs. e, p < 0.0001