A pair of researchers has begun to work out just how the rules that govern the translation of DNA into proteins evolved.
University of North Carolina-Chapel Hill's Charles Carter and the University of Auckland's Peter Wills performed regression modeling of transfer RNA groove recognition. There are 20 different kinds of tRNAs that each work with a different synthetase to help match that tRNA to the proper amino acid, UNC-CH notes at PhysOrg. Those 20 synthetases, Carter and Wills previously found, fall into two groups that likely arose from two ancestral enzymes.
In their new study, appearing in Nucleic Acids Research, the pair sought to determine whether tRNAs also fell into two ancient groups. While they did uncover different classes of tRNAs, they also found that though tRNA's anti-codon and synthetase are now separately located, they have a hidden, shared ancestry at the second base. This, UNC-CH says, supports the notion that there once were just two tRNAs, two synthetases, and two types of amino acids that then evolved.
"I think we have clarified the underlying rules and the evolutionary history of genetic coding," Carter said in a statement. "This had been unresolved for 60 years."