Study Challenges Long-Held Beliefs on Universal Genetic Code Evolution
January 29, 2025
The findings indicate that early life favored smaller amino acids over larger ones, with metal-binding amino acids being incorporated earlier than previously assumed.
The study identified over 400 families of amino acid sequences, with more than 100 families predating LUCA, highlighting a preference for amino acids with aromatic ring structures, such as tryptophan and tyrosine.
Coauthor Dante Lauretta noted that understanding the sulfur-rich nature of early life could significantly impact astrobiology and the search for extraterrestrial life on planets like Mars and Europa.
Criticism has been directed at the current understanding of genetic code evolution, which often relies on misleading laboratory experiments, such as the Urey-Miller experiment of 1952, that failed to produce sulfur-containing amino acids despite their abundance on early Earth.
The study suggests that earlier genetic codes may have existed but vanished over geological time, indicating that early life had specific preferences for certain molecular structures.
The genetic code, which translates DNA or RNA sequences into protein sequences using 20 different amino acids, is described as complex and nearly optimal for various biological functions.
A recent study led by Sawsan Wehbi, a doctoral student at the University of Arizona, calls for a revision of the traditional understanding of the evolution of the universal genetic code.
Published in the journal PNAS, the research reveals that the order in which amino acids were integrated into the genetic code contradicts long-held beliefs.
Wehbi's team utilized a novel analysis method to trace amino acid sequences back to the last universal common ancestor (LUCA), which existed approximately 4 billion years ago.
By focusing on protein domains instead of full-length protein sequences, the researchers were able to create a more accurate timeline for the recruitment of specific amino acids.
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Futurity • Jan 28, 2025
Genetic code's origin story may need a rewrite