text:  D9PGC_DazlKD_sh2 FACS-sorted differentiated GFP+tdTomato+ cells, day 9 differentiation, Dazl knockdown strain: C57BL/6 129SV mixed; gender: male; cell type: primordial germ cells (PGCs) generated from differentiated Oct4-GFP transgenic ES cells; days of differentiation: 9; shRNA: Dazl knockdown