Primordial Soup Lives Again
After decades of languishing in a cardboard box, unanalyzed vials from a famous chemistry experiment have been brought back to the lab, revealing new clues to the beginnings of life on Earth.
Over 50 years ago, Stanley Miller, then a 23-year-old graduate student, conducted an experiment that is now a staple of biology. Miller and his adviser, Nobel laureate Harold Urey, showed that amino acids, the building blocks of proteins, could be made from a cocktail of basic precursors, the so-called primordial soup.
A research team led by Miller’s former graduate student Jeffrey Bada analyzed leftovers from a variation on this experiment. The researchers report in the Oct. 17 Science that remnants from an experiment conducted with a simulated volcanic environment contain an even larger number of biologically important amino acids.
Bada and lead author Adam Johnson, a biochemist at Indiana University, Bloomington, noticed that some of the vials’ contents were created in the presence of a stream of water vapor, which simulated the local environment of a volcano. The team carefully reconstituted the dried material in these vials, and analyzed the contents with modern techniques.
The team not only identified amino acids similar to the ones Miller reported in 1953 from the experiment without the steam jet, but also identified 10 types of amino acids not found in the original setup. Bada’s team concludes that the infusion of a jet of steam creates a more diverse mixture of amino acids.
“The model is that you have these small pockets, volcanic hot spots,” explains Bada, in which a volatile reducing atmosphere, one in which chemicals are more likely to react with one another, may have produced amino acids.
The team’s reanalysis makes it plausible that a shallow tide pool tucked into the side of a volcano and a fortuitous bolt of lightning could have led to an abundance of amino acids.