Transcript On the Origin of Language

On the origin of the genetic code
Eörs Szathmáry
Collegium Budapest
Eötvös University
The structure of the genetic code
Variants of the common code
Amino acid biosynthesis in E. coli
Coevolution chart
• Precursor-product
pairs in biosynthesis
• Dashed boxes are
hypothetical
intermediate stages
• Italicised codons do
not match coevolution
predictions
Constraints on codon reshuffling
for statistical investigations
3 ways of code evolution
Forces may have changed in strength
Cofactor use by aptamers
From RNA to protein
• Gradual lose of
scaffold
• Amino acids to
peptides to proteins
• Not very well worked
out
Piecewise evolution of tRNA
Proteins from pieces
Superfolds
Some more proteins
Ribosomal proteins cannot fold by
themselves
Tryptophan-binding aptamers
The smallest typtophan binder
• The anticodon is CCA
• 13 fully conserved
nucleotides (26 bits of
information)
• Selective among
hydrophobic changes
An interesting idea?
• First two bases of a codon implied in synthesis of
amino acids originating from the reductive citric
acid cycle