Whole genome amplification of the embryos was performed using the PEPLI-g Midi Kit (Qiagen). Briefly, single cell or single blastomere was transferred into PCR tubes containing reconstituted buffer D2 (7 μL), and then incubated at 65°C for 10 min, before the addition of stop solution (3.5 μL) and MDA master mix (40 μL) and incubation at 30°C for 16 h. The DNA preparation was diluted with ddH2O (3:100), and 1 μL of the diluted DNA was used for PCR analysis.