Cyanide may have been key to origin of life

It sounds odd, but cyanide may have been a key ingredient in the origin of life on early Earth, according to a study. Researchers found that a mixture of cyanide and copper, when irradiated with ultraviolet (UV) light, could have produced simple sugars that formed the building blocks of life on our planet.

“One story for the origin of life is what we call the RNA world,” said Zoe Todd from the Harvard University in the US. “In order to make something like an RNA nucleotide, you need these sugars. This shows that process was plausible on the early Earth,” said Todd, researcher in the study published in the journal Royal Society of Chemistry.

A key step in showing that the hypothesis was plausible came in 2012, when scientists in the UK demonstrated that the system could produce simple sugars such as glycolaldehyde and glyceraldehyde.

Those tests were performed under ideal conditions - with relatively high concentrations of both cyanide and copper, and powerful lamps that generated high-energy, 254-nanometre wavelength light.

However, previous research has shown that early Earth would have experienced a range of wavelengths shorter than typical on the planet's surface today. Todd and Dimitar Sasselov, a professor at Harvard, set out to test the system under those conditions.

They combined small amounts of cyanide and copper in an airtight quartz container and then hit the solution with lower-intensity light from tunable xenon lamps. Using prisms, Todd was able to separate the light into different wavelengths, and target the system with a specific wavelength for hours at a time before running tests to confirm the reaction was actually taking place.

By adjusting the system based on specific conditions which molecules are present in an atmosphere and intensity of the UV light produced by nearby stars - researchers could use the system to model whether the reaction could operate on other planets, Todd said.