Ribose may have helped keep life’s boron chemistry alive

A sugar found in meteorites may have played a double role in the chemistry that preceded life on Earth, according to reporting by Nautilus on a study published in Scientific Reports.

The research examines ribose, a fragile sugar that forms part of RNA. RNA is important in living organisms because it helps store and use genetic information, and many scientists think it was involved in the earliest stages of life. The problem is that ribose breaks down readily, especially when heated, making it difficult to explain how enough of it could have survived in the harsh environments of the young Earth.

The study proposes that ribose may have helped solve that problem itself. When ribose interacts with borate, a compound containing boron, oxygen and hydrogen, the borate can shield the sugar from chemical breakdown. The new findings suggest the relationship also worked in the other direction: ribose encouraged borate minerals to dissolve, leaving more boron in the surrounding water.

A fragile ingredient in an ancient chemical mixture

Scientists investigating life’s beginnings often recreate possible early-Earth reactions in the laboratory. These experiments can reveal how individual chemicals behave, but purified ingredients and carefully controlled conditions may not capture the complicated interactions found in natural settings.

The researchers therefore used actual minerals, including borate crusts collected from hot springs at Puga in India’s Himalayas. The site contains enough boron for deposits of borate salt to crunch beneath visitors’ feet. Yet even these unusually boron-rich waters contain only a small fraction of the concentration used in some laboratory experiments.

That difference matters because boron-bearing minerals generally dissolve poorly. Much of the element becomes part of solid crystals rather than remaining in the water, where it could participate in reactions. The experiments described by Nautilus found that ribose can interfere with the formation of those solid grains and help borate minerals dissolve. As a result, a larger supply of boron remains available in solution, while the dissolved borate helps preserve the ribose.

This creates a possible feedback loop. A mineral compound protects a key organic molecule, and that molecule helps keep the mineral compound in a chemically useful form. Such a process could have made conditions more favourable for the increasingly complex reactions needed before biology appeared.

Meteorites, hot springs and early Earth

The Earth of roughly four billion years ago was unlike the present planet. Its atmosphere contained little oxygen, volcanic activity was more intense, and its surface included sparse volcanic regions and oceans rich in iron. Meteorites from the young Solar System were also striking the land frequently, delivering water and carbon-containing compounds.

Nautilus reports an estimate that about a million tonnes of carbon may have arrived each year during this period. The Murchison meteorite, which fell in Victoria in 1969, provides a sample of the kinds of material that may have reached Earth. Scientists have found ribose and other sugars in it, while people who collected pieces after the fall noticed a strong smell resembling kerosene from its carbon-rich contents.

Once delivered, these compounds could have accumulated in places where their arrival exceeded the rate at which they were destroyed. Shallow lakes and pools, for example, could have concentrated material as water evaporated. Such settings may have supplied the chemical mixtures in which minerals, water and organic compounds interacted over long periods.

Origin-of-life studies have traditionally focused on the way minerals might have helped organic chemistry become more elaborate. The new work turns the relationship around as well, asking how organic molecules may have altered the minerals around them.

Chemistry before biology

If ribose and related compounds kept more boron dissolved, they may also have influenced which minerals formed on the early surface of Earth. Ribose was probably uncommon, but ethylene glycol and glycerol can also bind to borate. Their effects on natural mineral deposits remain to be tested.

The researchers suggest that the implications may extend beyond boron. Carbon-containing molecules can interact with minerals involving more abundant elements, including silica and calcium. If so, the chemical mixtures delivered by meteorites or produced on Earth may have affected the formation of rocks and mineral deposits before living organisms existed.

Modern organisms visibly reshape geology by producing shells and coral structures through biomineralisation. The study raises the possibility that non-living carbon compounds began influencing mineral formation much earlier, during the transition from geochemistry to biology.

Whether those interactions changed whole landscapes is still unknown. But examining them could make laboratory models of life’s origins more realistic and help scientists assess which environments on other worlds might support the emergence of life.