Drying puddle sparked life on Earth

London: The first spark that triggered life on the early Earth may have occurred in an environment similar to a drying puddle, researchers, including one of Indian-origin, suggest.

 

Anyone who’s ever noticed a water puddle drying in the Sun has seen an environment that may have driven the type of chemical reactions that scientists believe were critical to the formation of life on the early Earth.

 

Researchers showed that polypeptides, important molecules of contemporary life, can be formed simply by mixing amino and hydroxy acids then subjecting them to cycles of wet and dry conditions.

 

The research supports the theory that life could have begun on dry land, perhaps even in the desert, where cycles of night-time cooling and dew formation are followed by daytime heating and evaporation. 

Nicholas Hud, a professor at Georgia Institute of Technology, said: “It looks like dry land would have provided a very favourable environment for getting the chemistry necessary for life started.”

 

The idea for combining chemically similar amino acids and hydroxyl acids was inspired by the fact that polyesters are easy to form by repetitive hydration-dehydration cycles and the fact that esters are activated to attack by amino group of amino acids. 

“Over the course of a very simple chemical evolution, the polymers progress from having hydroxy acids with ester linkages to amino acids with peptide linkages,” Hud said. 

 

“The hydroxy acids are  replaced through the wet and dry cycles because the ester bonds holding them together are not as stable as the peptide bonds,” he said. Researchers put the amino and hydroxy acid mixtures through 20 wet-dry cycles to produce molecules that are a mixture of polyesters and peptides, containing as many as 14 units.  After just three cycles, and at temperatures as low as 65 degrees Celsius, peptides consisting of two and three units began to form.