A lot happened in the hundreds of millions years separating the first and last eukaryotic common ancestors, but when and how most features arose remains a mystery.
The discovery that a group of cell-infecting bacteria lived roughly 2 billion years ago stirs a longstanding controversy around which came first: phagocytosis or mitochondria.
Alan Aderem earned his PhD while under house arrest for protesting apartheid in South Africa. His early political involvement has guided his scientific focus, encouraging fellow systems biologists to study immunology and infectious diseases.