Evidence from glycine transfer RNA of a frozen accident at the dawn of the genetic code
2008
The First tRNA and the Origin of the Genetic Code
Sample size: 466
publication
Evidence: moderate
Author Information
Author(s): Bernhardt Harold S, Tate Warren P
Primary Institution: University of Otago
Hypothesis
Glycine tRNA was the first tRNA, providing a mechanism for the origin of the genetic code.
Conclusion
The retention of a specific sequence in glycine tRNA over billions of years supports the idea that glycine was the first amino acid encoded in the genetic code.
Supporting Evidence
- 96% of analyzed glycine tRNA sequences have a CCA sequence upstream of the intron insertion position.
- The CCA sequence is conserved in nearly all contemporary glycine tRNA molecules.
- Previous studies suggest glycine was one of the first amino acids incorporated into the genetic code.
Takeaway
Scientists think glycine was the first building block for proteins, and they found clues in the genetic code that support this idea.
Methodology
Analysis of 466 glycine tRNA gene sequences from bacteria, archaea, and eukaryote cytoplasm.
Limitations
The study does not definitively identify an ancestral glycine tRNA gene sequence.
Digital Object Identifier (DOI)
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