NASA’s latest discovery challenges the way we think about life on Earth and beyond

Current findings from researchers UCLA and NASA’s Goddard Space Flight Center are shaking our understanding of the molecular basis of life. A groundbreaking study has found that the origin of life on Earth may not have been as narrowly defined by “left-handed” molecules as previously thought. The discovery challenges the long-held belief that the building blocks of life – particularly amino acids and sugars – are strictly determined by the chirality, or “handedness,” of molecules.

In a new article published in Nature communicationScientists discovered evidence that early RNA structures may have been more flexible in their molecular preferences. This finding has profound implications, not only for our understanding of the origins of life on Earth, but also for the search for life elsewhere in the universe.

Chirality and its crucial role in molecular biology

In molecular biology Chirality refers to the property of molecules existing in two mirror-image forms. Similar to human hands, these mirror-image molecules cannot be placed on top of each other. One form is typically referred to as “left-handed,” while the other is referred to as “right-handed.” These chiral forms are fundamental to the structure and function of the building blocks of life.

For example, DNA and RNAthe molecules that encode genetic information contain sugars that are always “right-handed.” Likewise, the amino acids that make up proteins are predominantly “left-handed.” The fact that life on Earth uses a certain “handedness” for these molecules is called Homochirality. This unique molecular preference has long been considered essential to the emergence of life, making it one of the defining features of biology on our planet.

However, the new study challenges this idea rigid molecular bias. The research led by Irene ChenProfessor of chemical and biomolecular engineering at UCLA, suspects that the early stages of life may not have been governed by such hard-and-fast rules. Instead, early RNA molecules could have been more diverse in their molecular preferences, with no clear predisposition to “left-handed” amino acids or “right-handed” sugars.

Breaking new ground: The unexpected flexibility of RNA

This new research focuses on small ribozymes RNA molecules capable of catalyzing chemical reactions. Previous models of the origin of life assumed that ribozymes played a key role in early biochemical reactions that would eventually lead to the emergence of life DNA and proteins. Traditionally, scientists believed that RNA had a strong chemical tendency to use a particular form of chirality, either left- or right-handed molecules, similar to modern biological systems.

To test this assumption, the UCLA and NASA The researchers focused on understanding whether ribozymes can catalyze the formation of both left- and right-handed amino acids. Using a series of ribozymes and amino acid precursors under controlled laboratory conditions that simulated early Earth environments, the team found that some Ribozymes could produce both species Amino acidsdepending on the conditions. This finding was unexpected because in current biology, dextrorotatory ribozymes typically produce levorotatory amino acids, reflecting a strict molecular preference.

“The experiment showed that ribozymes can prefer either left- or right-handed amino acids, suggesting that RNA worlds in general do not necessarily have a strong bias for the shape of amino acids that we currently observe in biology,” he said Irene Chen.

This discovery implies that the RNA world– the hypothetical period in the early history of the earth, as RNA molecules were the central players in the emergence of life – perhaps more chemically diverse than originally thought. The molecular structures of life may have been shaped by a combination of chemical randomness and environmental influences, rather than being strictly limited to a chiral form.

A new model for the origin of life: not chemical determinism, but evolutionary pressure

The implications of this discovery are far-reaching. If the first life forms on Earth were not characterized by a preference for “left-handed” amino acids and “right-handed” sugars, then the molecular structures of early life could have been much more variable. This suggests that the emergence of life on Earth may not have occurred predetermined chemical event. Instead, the specific chirality of life’s building blocks may have been shaped by later evolutionary pressures as molecules began to reproduce and evolve themselves over time.

Alberto Vazquez-Salazara UCLA postdoctoral fellow and study author, noted, “The results suggest that the ultimate homochirality of life may not be the result of chemical determinism but may have arisen from later evolutionary pressures.”

This new model shifts the origin of life narrative from a singular, deterministic process to one that emphasizes adaptability and variability. It also opens the door to new theories about the chemical pathways that led to the development of Life on Earth and possibly elsewhere in the cosmos.

Implications for the search for extraterrestrial life

The discovery of The unexpected flexibility of RNA in early biochemical reactions could also have profound implications for astrobiology – the study of Life beyond earth. If the molecular structures of the early Earth did not follow a strict chiral pattern, then life elsewhere in the universe might have followed different chemical pathways. This challenges the assumption that extraterrestrial life must necessarily conform to the same chiral preferences that dominate life on Earth.

Jason Dworkin, A senior scientist at NASA’s Goddard Space Flight Center and co-author of the study emphasized that these findings could change the way we search for signs of life on other planets. “Understanding the chemical properties of life helps us know what to look for in our search for life across the solar system,” Dworkin said.

This new perspective has direct implications for NASA’s ongoing efforts to explore the origins of life in space, including missions such as OSIRIS RExwhich recently returned samples from the asteroid Bennu. These samples could provide crucial clues about the role of chirality in forming the building blocks of life and help scientists better understand the diversity of possible life forms in the cosmos.

Looking ahead: The future of the building blocks of life

The research led by UCLA and NASA opens a new chapter in the ongoing quest to understand the origins of life, not just on Earth but potentially throughout the universe. With this new flexibility in mind, scientists will continue to explore how early life might have evolved, both here on Earth and on other planets or moons in our solar system. By studying samples from asteroids and moons, future missions could reveal even more about the chemistry of the building blocks of life and how they differ from what we know today.

The study also raises the question: Could life elsewhere in the universe follow completely different rules, dictated by different chiralities or completely novel molecular structures? As we advance space exploration, this research provides a new framework for exploring extraterrestrial lifeThis encourages scientists to expand their search for extraterrestrial life beyond the boundaries of Earth’s molecular biases.