ONE of the key assumptions about the origin of life is under fire. The widely held belief that all life on Earth today originated from a single ancestor cell is being challenged by a theory that several different lineages evolved independently.
In his “doctrine of common descent”, Darwin was the first to argue that all life on the planet began with a single “primordial form”, generally interpreted nowadays as the first living cell. Not so, says Carl Woese of the University of Illinois at Urbana-Champaign. In a controversial new theory published this week, he argues that the three fundamental types of cells that form the building blocks of present-day life actually evolved…
