PGCLC aggregates were trypsinased and sorted into cold PBS. The cells were centrifuged at 2,000 rpm for 3 min following liquid nitrogen snap freezing. Total RNA was extracted using ZR-Duet DNA and RNA Mini Prep kit (Zymo). The genotype of embryos was determined by PCR. RNA quality was measured by 2100 bioanalyzer (Agilent technologies). RNA and cDNA were prepared by NEBNext® Single Cell/Low Input RNA Library Prep Kit for Illumina® according to the manufacturer's instructions.