Contrary to textbook models, many genes that should be “off” in embryonic stem cells and specialized adult cells remain primed to produce master regulatory proteins, leaving those cells vulnerable to identity changes.
Researchers have manipulated mouse fibroblasts and turned them into cells with such developmental elasticity that they appear identical to embryonic stem cells.
Researchers have developed a cell culture test for assessing a compound’s genetic toxicity that may prove dramatically cheaper than existing animal tests.