Produced by: Manoj Kumar
Long-held beliefs about the order of life’s building blocks are being challenged by a study in the Proceedings of the National Academy of Sciences. Researchers now suggest a more complex and nonlinear process.
Scientists from the University of Arizona argue that amino acids, the building blocks of proteins, may not have emerged in the clear sequence previously believed, reshaping our understanding of early evolution.
Focus on amino acids may have overshadowed critical precursors like RNA and peptides, which likely played a pivotal role in the transition from non-living chemistry to life, researchers assert.
Using advanced software and National Center for Biotechnology Information data, researchers mapped protein domain evolution, finding unexpected patterns in how amino acids emerged over time.
Tryptophan, once thought to be the last amino acid added to the genetic code, was found more common in early life forms, suggesting a non-linear and more intricate evolutionary process.
Early life may have used multiple genetic "codes" simultaneously, relying on non-standard amino acids likely formed in environments like alkaline hydrothermal vents, a key to understanding life’s beginnings.
Amino acids may have originated from various regions of early Earth, challenging the assumption that their abundance dictated their order in the genetic code, according to lead author Sawsan Wehbi.
Wehbi compares early amino acid chains to "wheels that existed long before cars," highlighting how these molecules weren’t specific to organisms but foundational to life.
This breakthrough not only reframes life’s origins on Earth but also guides the search for life elsewhere, offering clues about how life might arise in different environments across the universe.