I. The Origin of Cellular Life on Earth
II. Protocell Membranes
III. Non-Enzymatic Copying of Nucleic Acid Templates
Part II: Protocell Membranes
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Szostak begins his lecture with examples of the extreme environments in which life exists on Earth. He postulates that given the large number of Earth-like planets orbiting Sun-like stars, and the ability of microbial life to exist in a wide range of environments, it is probable that an environment that could support life exists somewhere in our galaxy. However, whether or not life does exist elsewhere, depends on the answer to the question of how difficult it is for life to arise from the chemistry of the early planets. Szostak proceeds to demonstrate that by starting with simple molecules and conditions found on the early earth, it may in fact be possible to generate a primitive, self-replicating protocell.
In Part 2, Szostak focuses on work from his lab studying the membrane components of a simple protocell and in Part 3 of his lecture, he describes experiments to investigate nucleic acid replication by chemical rather than enzymatic mechanisms.
Early in his research career, Dr. Szostak made important contributions to the field of genetics. These included construction of the first yeast artificial chromosome and furthering our understanding of the function of telomeres, work for which he shared the Nobel Prize in Physiology or Medicine in 2009. By the 1990s, however, Szostak had redirected his research to understanding how life on earth may have first emerged. He began his studies in this area by attempting to construct an RNA molecule that could self-replicate. His lab now focuses on developing a simple artificial cell that can grow and evolve in response to a changing environment.
Szostak received his B.S. in biology from McGill University and his PhD in biochemistry from Cornell University. Currently, he is a Professor of Genetics at Harvard Medical School and an Investigator at Massachusetts General Hospital and the Howard Hughes Medical Institute.
- Dianne Newman iBioSeminar: Microbial Diversity and Evolution
- Nicole King iBioSeminar: Choanoflagellates and the Origin of Animal Multicellularity
- Julie Huber iBioMagazine: Microbial Oceanography
- Jack Szostak Short Clip: Evolution of Membranes
Original papers: Mansy SS, Schrum JP, Krishnamurthy M, Tobé S, Treco D, and Szostak JW. Template-directed Synthesis of a Genetic Polymer in a Model Protocell. Nature, 2008; 454:122-5.
Zhu TF and Szostak JW. Coupled growth and division of model protocell membranes. J. Am. Chem. Soc., 2009, 131: 5705–5713.
Ricardo A and Szostak JW. Origin of life on earth. Scientific American, 2009; 301:54-61.
Schrum JP, Zhu TF and Szostak JW. The Origins of Cellular Life. Chapter in, “The Origins of Life”, eds. D Deamer and JW Szostak, 2010, CSH Press.