Long-sought mechanism for cell development has at last been found.

We have had personal organisers for years, from the Filofax and PalmPilot to the calendar on the modern smartphone. To those you can now add a “person” organiser that takes managing stuff to a decidedly higher plane. We’re talking organising cells to become distinct bits of human.

Researchers, led by Ali Brivanlou from the Rockefeller University, New York, US, have found the signal that causes cells in the developing human embryo, which start off “pluripotent” – able to become any type of cell – to choose a future career, in this case getting to work in the nervous system.

The early embryo is already known for amazing feats, not least of which is divvying up cells into three groups or “germ layers”. Cells from the “endoderm” become, among other things, stomach and lung; the “mesoderm” forms muscle and bone; and the “ectoderm” morphs into skin, teeth, and the all-important nervous system. It’s called “gastrulation”.

But studying all this in real human embryos crosses an ethical line.

To stay on the right side of that line the researchers had previously created a “gastruloid”. This is a cluster of human embryonic stem cells, a millimetre or so across, that is basically a working model of an embryo in a Petri dish.

Under the action of a protein called Bone Morphogenetic Protein 4 (BMP4) the team coaxed those generic cells, breathtakingly, into becoming the three germ layers.

But there was always a missing piece to the puzzle.

Read the full article in Cosmos magazine here