The transformation of a fertilised egg into a tiny living embryo ranks among nature’s most impressive feats. Now scientists have replicated this critical step towards a new life for the first time, growing an artificial mouse embryo from stem cells in the lab.
The cells, grown outside the body in a blob of gel, were shown to morph into primitive embryos that perfectly replicated the internal structures that emerge during normal development in the womb.
The scientists let the artificial embryos develop in culture for seven days – about one third of the way through the mouse pregnancy. By this point the cells had organised into two anatomical sections that would normally go on to form the placenta and the embryonic mouse.
The mouse embryo breakthrough is not designed to grow mice or babies
outside the womb, but to open a new window on the embryo’s development
just prior to implantation.
Photograph: Redmond Durrell / Alamy/Alamy