Junying Yu now assumed she had no chance. Her scientific rival in Japan, Shinya Yamanaka, had sent mature mouse cells back to their embryonic origin. All that remained was for the work to be published. Soon he would do the same with human cells.
In 2003, Yu and her supervisor, UW stem cell pioneer James Thomson, had set out to reprogram human cells, unaware that Yamanaka was chasing the same improbable goal. If they succeeded, the scientists would capture the power of human embryonic stem cells without the ethically contentious destruction of embryos.