How sugar from outer space became one of the backbones of life on Earth
Ribose molecules came to Earth in meteorites and eventually became key parts of RNA. But how they survived in between has been a mystery.
The origins of life on Earth have long captivated humanity's curiosity. One avenue of inquiry involves examining how life's building blocks emerged from the primordial soup. A new study published in Scientific Reports provides fresh insights into a crucial step: how an outer space sugar may have helped sustain the conditions for its own survival on Earth.
Scientists theorize that life arose from a complex mixture of water, minerals, and carbon-containing molecules in our planet's primordial oceans, lakes, or hot springs. These environments underwent fluctuations in temperature, water flow, mineral surfaces, and evaporation, creating conditions conducive to evolving chemistry. Researchers attempt to replicate these processes in laboratories, often using purified chemicals and controlled mixtures.
However, this approach may overlook significant interactions present in nature's intricate chemistry.
One molecule under study is RNA, a vital component of genetic information storage and use in modern organisms. Its molecular backbone features a fragile sugar called ribose, which can degrade into a brown substance upon heating. Certain elements, like boron in the form of borate, can shield ribose from breaking down. Researchers often use simplified combinations of purified ingredients in experiments to study this effect.
However, a team of researchers sought to make these experiments more realistic by considering ancient rock, mineral, and fossil data. One such location is Puga, a field of hot springs in India's Himalayas. These hot springs contain an abundance of boron, which precipitates into crusts on the ground, leaving less boron and other elements in the water surrounding the springs.
Through their investigation, the researchers discovered that ribose itself plays a role in explaining how high concentrations of dissolved boron could have existed in ancient Earth fluids. They found that ribose aids borate mineral dissolution and prevents the formation of solid grains, thus keeping boron dissolved and available for chemical reactions. This new research suggests a reciprocal relationship between ribose and borate, with each protecting and enhancing the other.
Around four billion years ago, Earth's atmosphere was oxygen-poor and marked by intense volcanic activity, resulting in green, iron-rich oceans. Meteorites raining onto Earth's surface during this period could have delivered water and carbon compounds, including ribose. The Murchison meteorite, which landed in Victoria in 1969, contains ribose among its carbon-containing compounds.
The study highlights how the presence of ribose in early Earth's soups may have influenced the formation of minerals, thus shaping the planet's geology before the emergence of life. Further research is needed to determine the extent to which these interactions reshaped Earth's landscapes. Nevertheless, exploring these relationships can aid scientists in testing their theories on the origins of life.
Written by urgent.news from The Conversation AU's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
