Cellular evolution began in a communal environment in which the loosely organized cells took shape through extensive horizontal gene transfer, according to Carl Woese, a microbiologist at the University of Illinois at Urbana-Champaign.

His theory challenges the longstanding Darwinian assumption known as the Doctrine of Common Descent — that all life on Earth has descended from one original primordial form.
On the evolution of cells, Carl R. Woese, Proc. Natl. Acad. Sci. USA, 10.1073/pnas.132266999.