The chances are, this is the first you have heard of cyanosulfidic chemistry. Remember this moment – this is a scientific term that matters.
It’s a shame chemists can’t be more inventive with their field names. Physicists have the ear-pleasing “Big Bang cosmology” to explain the beginning of the universe. Biologists have “evolution” to account for the natural world being as we find it. Chemists, however, are doomed to stick to a tongue-twisting script, even when describing a huge discovery.
Cyanosulfidic chemistry is as big as the Big Bang because it finally answers a long-standing question: how did life arise? The term was coined in a paper published on 16 March by a team led by John Sutherland of Cambridge University. He and his colleagues have been trying to work out how, at some point in earth’s history, chemistry gave birth to biology.
In most of the thousands, maybe millions, of pools of water on the primordial earth’s surface, nothing epoch-making was happening. But in some of them, all the right chemicals were thrown together, and life began. We are familiar with a version of this story, but there are holes in the plot. Complex nucleic acid molecules such as RNA and DNA arose somehow to manufacture amino acids, and from them proteins, the building blocks of living organisms. That said, we are aware that proteins build DNA and RNA. So how was the first protein made? Or, for that matter, the first nucleic acid?
These aren’t the only eggs and chickens in the story. For instance, molecules known as lipids are also vital to life, and they require protein-based enzymes to build them – from instructions encoded in DNA and RNA. How on earth did all the ingredients form these necessary chemicals?
Sutherland and his colleagues have worked out that it didn’t require a miracle, just pools of water, some sunlight and some very simple molecules.
One of those small molecules is hydrogen cyanide, which is composed of carbon, hydrogen and nitrogen. All of these elements arrived on earth riding on rocks. The early earth was peppered with comets, and the energy released on impact easily enough created hydrogen cyanide in abundance. The other necessary ingredient is hydrogen sulphide, which, as a by-product of volcanic activity, was also abundant on the primordial earth.
Sutherland and his team have demonstrated that when hydrogen cyanide and hydrogen sulphide come together in the presence of ultraviolet light, the result can be nucleic acids, such as RNA and DNA. Similar ingredients, in slightly different conditions, produce protein-building amino acids and lipids. The reactions require metal catalysts, but metals were also abundant on the surface of the earth at the time life arose.
So, all that was required for the molecular machinery of life to arise was for all of the ingredients to come together in the same place under the right conditions. Those conditions are, basically, sunlit water. In its paper, the team describes a fistful of chemicals “developing over time in separate streams and pools”, then becoming mixed as those streams and pools flowed together. In other words, you can have both the chicken and the egg. The mistaken idea that one must precede the other has held us back for decades.
So the picture is, essentially, complete. As the researchers say, it still “has to be painted with broad brushstrokes”, but there is no need for chemists to hand-wave about how life got started, and there is certainly no need for miracles. All we need now is a memorable name for the breakthrough. You’ve probably forgotten its assigned moniker already. Doing great chemistry is all very well, but sadly, if this field is to get the attention it deserves, branding is going to matter, too.
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