Imperfect mimics

Reprogramming may not produce exact embryonic stem cell replicas

Pod people may look a lot like the real thing, but — as the fictional town of Santa Mira finds out in Invasion of the Body Snatchers — they are disastrously different. The same may be true for reprogrammed stem cells.

POTENTIAL QUESTIONED Comparisons of embryonic stem cells and reprogrammed stem cells (colony shown) are leading scientists to question whether the reprogrammed cells can fully forget their past.