Derivation of human embryonic stem cells from single blastomeres

This protocol details a method to derive human embryonic stem (hES) cells from single blastomeres. Blastomeres are removed from morula (eight-cell)-stage embryos and cultured until they form multicell aggregates. These blastomere-derived cell aggregates are plated into microdrops seeded with mitotically inactivated feeder cells, and then connected with neighboring microdrops seeded with green fluorescent protein-positive hES cells. The resulting blastomere-derived outgrowths are cultured in the same manner as blastocyst-derived hES cells. The whole process takes about 3-4 months.