BioTechniques News
Maddy Chapman
Original story from Texas A&M University (TX, USA).
Scientists unlock a groundbreaking discovery about the origins of life with absorption, fluorescence and Raman spectroscopy.
Scientists have long sought to understand the complex origins of intelligent life. Emerging during the hostile climate of primordial Earth, it remains unclear how biological systems not only formed but survived and persisted under extreme conditions. Now, researchers at Texas A&M University (TX, USA) are using light-based technologies to uncover new clues to help solve this evolutionary puzzle.
Peter Rentzepis, a professor in the Department of Electrical and Computer Engineering, and his research assistants Keyvan Khosh Abady and Negar Karpourazar, have achieved a significant breakthrough on the origins of molecular evolution. Their findings, published in Proceedings of the National Academy of Sciences, offer new insights into the beginning of life on Earth.
Unraveling a decades-long puzzle
When intelligent life formed, DNA became the primary biological code, diverging from single-stranded RNA. When this occurred, a chemical called thymine replaced uracil as one of the molecule’s main building blocks.
However, this change has long perplexed scientists, as thymine is more prone to ultraviolet (UV) damage. This would seemingly make it a poor replacement on early Earth, where the lack of a protective ozone layer exposed lifeforms to extreme UV radiation from the Sun. The apparent paradox prompted Rentzepis’ team to investigate why Mother Nature made such an unconventional choice.
The team launched a study comparing thymine and uracil under controlled UV conditions designed to mimic the intense radiation environment of primordial Earth. Using biophotonics – an interdisciplinary field that uses light-based spectroscopic methods, including absorption, fluorescence and Raman spectroscopy – to analyze the molecules, they made a significant discovery.
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“We found that thymine tends to direct UV damage into a more reversible form, suggesting that early genetic molecules may have survived intense sunlight not by avoiding damage, but by controlling it and making it easier to self-repair,” explained Khosh Abady. “In that sense, thymine may have acted as a molecular sunscreen, absorbing harmful UV energy and keeping the damage confined to the genetic bases rather than allowing it to harm more vulnerable parts of the molecule.”
Microscopic discovery, big implications
The ongoing scientific implications of this discovery are vast, affecting a variety of areas of study as researchers continue to learn more about who we are and where we came from.
Measurements developed by the team also establish a new reference framework that could eventually support important research like detecting pathogens and checking whether UV disinfection systems are working properly.
“The distinct spectral signatures we measured could support applications in faster, more sensitive pathogen detection and in monitoring whether UV disinfection has effectively inactivated microorganisms, particularly in water-treatment systems,” added Khosh Abady.
More answers on the horizon
In the future, Rentzepis and his team plan to extend this work to an earlier stage in the origin-of-life process by investigating the forces that made thymine, uracil and other components of early genetic systems come together in the first place.
“We hope to explore whether life’s chemical building blocks formed and assembled entirely on Earth or whether some were delivered to our planet from elsewhere by meteorites and later incorporated into early genetic systems,” continued Khosh Abady. “We are grateful to Texas A&M University and our research sponsors for supporting this work and enabling us to explore fundamental questions about life’s origins.”
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