Tracing the Origins of Life

PRIMORDIAL SOUP: Scientists believe extremely hot, cold and acidic environments helped create the conditions for life on Earth.
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PRIMORDIAL SOUP: Scientists believe extremely hot, cold and acidic environments helped create the conditions for life on Earth.

It is chemistry’s grand question: How did Earth evolve from a primordial soup of simple nonliving molecules to a planet filled with the infinitely complex reactions and structures that define life?

With the help of a three-year $1 million grant from the W.M. Keck Foundation, a few Brandeis scientists hope to raise the curtain on this mystery. Chemists Irv Epstein, Li Deng and Bing Xu, and physicist Michael Hagan will research key steps in the epochal transition from simple molecules to life on Earth.

They’re following in the footsteps of earlier chemist-explorers who discovered that simple molecules, such as water, methane and ammonia, could react to produce more complex molecules, like amino acids and sugars. Recent studies have shown that much more complicated molecules, such as nucleic acids, can react to start building complex cell-like structures.

The Brandeis group will focus on the puzzling gap between the formation of relatively simple molecules and more complex entities.

“We are not looking to answer the question ‘How did life definitively evolve on Earth?’” Epstein says. “Rather, we are exploring possible avenues of how life could emerge from nonliving matter.”

They’ll study the evolution of molecular catalysts that are autocatalytic (able to react to produce more of themselves) and capable of self-organizing (spontaneously arranging themselves in intricate patterns by using energy from their surroundings). These two qualities lead to more complex reactions and structures — the key components necessary for life.

The chemists will subject the molecules to extremely hot, cold and acidic environments — re-creating the conditions in which these chemicals might have reacted 3.8 billion years ago — on the theory that such extreme conditions would likely have increased the types and complexities of molecular reactions.

This research may also answer some of science’s nagging, if esoteric, mysteries. For example, why do all amino acids found in living systems have the same chirality, or handedness, when nature is perfectly capable of producing either left or right chirality?

“We are hoping to explore how these motifs we see all around us today could arise,” Hagan says. “We’ll never know for sure what happened back then, but this research will help us understand what could have happened.”

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