By Laurel Hamers
The evolutionary path from single-celled organisms to complex species with higher-order thought processes has been mapped out with some degree of certainty, but how the earliest life forms appeared has proven a more difficult question. What conditions prompted organic molecules to assemble into the building blocks of life?
At the recent Origin of Life Symposium in Lille Auditorium, hosted by the MBL Physiology course, a panel of four distinguished scientists shared their research and opinions on this complex topic.
“What makes this a really important question is not only that it’s fundamental to how we understand biology as a process of living systems, but it’s also really important to how we think about the fate of this planet,” said Jennifer Lippincott-Schwartz, Physiology course co-director and a principal investigator at the Eunice K. Shriver National Institute of Child Health and Human Development.
Center of the Milky Way Galaxy IV – Composite. Credit: NASA/JPL-Caltech/ESA/CXC/STScI – NASA JPL Photojournal: PIA12348.
The first speaker, MBL Distinguished Scientist Mitchell Sogin, gave a broad overview of historical and current theories on the origin of life, with an emphasis on the role of geological diversity. Different geological microenvironments could have generated the building blocks that eventually combined to create habitable environments, he said.
Jack Szostak, Professor of Genetics at Harvard Medical School and 2009 Nobel Laureate in Physiology or Medicine, took the stage next. He described the problem as a step-by-step process.
“We’re not worried so much about defining exactly where life began,” he said. “I think what’s important is to understand the pathway. There’s a whole series of processes from simple chemistry to more complicated chemistry, building up the building blocks of biology,” Szostak said. “The goal for the field for the moment is to understand one continuous pathway from chemistry to biology.”
Nilesh Vaidya, a postdoctoral fellow at Princeton University, discussed research on spontaneous RNA assembly that he had carried out as a graduate student at Portland State University. By demonstrating that small RNA fragments can form cooperative networks that evolve toward greater complexity, he argued that early RNA-like molecules might have used a similar tactic to support the emergence of early life.
Tony Hyman, managing director of the Max Planck Institute of Molecular Cell Biology and Genetics, offered a different perspective, focusing on how cytoplasmic organization may have fostered an environment conducive to the formation of early life. He argued that phase separation of organic molecules due to cytoplasmic organization would concentrate these molecules in certain spaces and facilitate reactions that might not occur at lower concentrations.
A group discussion at the end helped symposium attendees to integrate the topics that the four researchers had presented.
The purpose of the symposium was not to reach a conclusion about the origins of life—the speakers all admitted that this was a daunting, and likely impossible, task. Rather, by bringing together eminent researchers in the field, the symposium organizers hoped to foster discussion between scientists addressing the same question from different angles.