Review Volume 3, Issue 5 pp 494—508

Figure 1. Generation of pluripotent human embryonic stem cell lines. Generation of human embryonic stem cell (hESC) lines involves several steps. Donor embryos are first obtained after in vitro fertilization or by egg activation (parthenogenetic embryos), and allowed to develop in vitro. Pluripotent cells are then isolated either from the inner cell mass of pre-implantation blastocysts or from 4, 8, or 16 -cell stage morulae. Finally, isolated cells are plated in defined hESC medium with or without feeder cell layers to propagate and select for pluripotent cell populations. These processes have resulted in hESC lines able to generate tissues from all three embryonic germ layers and the germline.