Scientists are investigating the complex origins of intelligent life on Earth, focusing on how biological systems formed and survived under extreme conditions. Researchers at Texas A&M University have made significant strides in understanding this mystery through light-based technologies. Dr. Peter Rentzepis, a professor in the Department of Electrical and Computer Engineering, along with research assistants Keyvan Khosh Abady and Negar Karpourazar, recently published their findings in the Proceedings of the National Academy of Sciences (PNAS).
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Their work addresses a long-standing puzzle: the shift from single-stranded RNA to DNA as the primary biological code. This evolution involved the replacement of uracil with thymine, raising questions because thymine is more susceptible to ultraviolet (UV) damage. Given the harsh UV radiation on early Earth, the choice seemed paradoxical. To explore this, Rentzepis' team conducted a study that compared the properties of thymine and uracil under controlled UV conditions that replicate primordial Earth's radiation.
Utilizing biophotonics—an interdisciplinary field that employs light-based spectroscopic methods—they discovered that thymine tends to localize UV damage into a more reversible form. Khosh Abady stated, "We found that thymine may have acted as a molecular sunscreen, absorbing harmful UV energy and keeping the damage confined to the genetic bases, making it easier for these early genetic molecules to self-repair."
The implications of this discovery are far-reaching, potentially affecting areas such as pathogen detection and UV disinfection processes. The research team has developed new measurement techniques that may lead to faster and more sensitive methods for detecting pathogens and ensuring effective UV disinfection in water-treatment systems.
Looking ahead, Rentzepis and his team plan to delve deeper into the origin-of-life process, specifically investigating how thymine, uracil, and other early genetic components came together. Khosh Abady expressed hopes to explore whether these building blocks originated on Earth or were delivered by meteorites. They recognize the support from Texas A&M University and their sponsors for enabling this innovative research.