Pulling backwards

extinguished by the transfer. But the extent of the transformation is not yet clear. “It’s possible that what we are doing is turning everything into an oocyte,” says Gurdon. But he believes that oct4 expression is a good sign that the cells are at least headed toward becoming stem cells. Stem cell characteristics may develop only through sequential inductive events. But the optimists are hoping that there is a single extract that will do the entire conversion. The success of the current experiments, says Gurdon, is “one of the more compelling reasons for believing that to be true.”