library_construction_protocol: The whole day 2 embryoid bodies with hPGCLCs and day 2 DE cells (around 1.5-1.7 million cells) were collected for chromatin immunoprecipitation using the SimpleChIP Enzymatic Chromatin IP Kit (Magnetic Beads) (Cell Signaling Technology, 9003). Briefly, The cell pellets were washed twice with cold PBS containing 0.1% BSA and then fixed with paraformaldehyde. Following chromatin digestion with Micrococcal Nuclease, 2% volume of nuclei lysate was removed and stored at -80 °C as input control while the rest of the lysate was subjected to immunoprecipitation with anti-HA (Cell Signaling Technology, 3724) or anti-Myc (Cell Signaling Technology, 2276) antibody. After elution of chromatin, reversal of cross-links and DNA purification, the ChIP and input DNA were prepared for sequencing using the KAPA HyperPrep Kit following the manufacturer's instructions. Quantified and validated libraries were subjected to single-end or paired-end sequencing on HiSeq 4000 sequencing system (Illumina).