Dr. Szostak's laboratory research is focused on the origin, early evolution and laboratory synthesis of simple living systems. The complexity of modern biological life has long made it difficult to understand how life could emerge spontaneously from the chemistry of the early earth. The key to resolving this mystery lies in the simplicity of the earliest living cells. Through efforts to synthesize extremely simple artificial cells, he hopes to discover plausible pathways for the transition from chemical evolution to Darwinian evolution. He views the two key components of a primitive cell as a self-replicating nucleic acid genome, and a self-replicating boundary structure. He has recently discovered a simple and robust pathway for the coupled growth and division of a model primitive cell membrane. He is currently engaged in the design and chemical synthesis of modified nucleic acids that may be able to replicate without enzymes. By combining self-replicating nucleic acids and membranes we hope to generate model protocells that will allow us to observe the spontaneous emergence of Darwinian behavior.