Study Challenges Long-Held Beliefs on Universal Genetic Code Evolution

January 29, 2025
Study Challenges Long-Held Beliefs on Universal Genetic Code Evolution
  • 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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Genetic code's origin story may need a rewrite

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