Most media reports on stem cell biology trace the field's origin to two key papers published in 1981.1,2 But Leroy Stevens at the Jackson Laboratory in Bar Harbor, Maine, laid the groundwork in mice from the 1950s through the 1970s, manipulating bizarre growths called embryoid bodies,3 to see what these cells would become. Embryoid bodies formed when cancer cells were transplanted into mouse abdomens. At first they appeared to be a ring of cells enclosing blood, debris, and a few unspecialized cells. Over time, differentiated cells would appear, sometimes even forming a beating mass of contractile tissue, as well as other hints of a body.
John Gearhart Now stem cell biology has come full circle, with one of the two groups that cultured the first human embryonic stem (ES) cells in 19984 reporting on the isolation of the most promising type of human stem cell yet: embryoid body-derived cells, or ...
