We advocate for a tRNA-rather than an mRNA-centric model for evolution of the genetic
code. The mechanism for evolution of cloverleaf tRNA provides a root sequence for radiation
of tRNAs and suggests a simplified understanding of code evolution. To analyze code
sectoring, rooted tRNAomes were compared for several archaeal and one bacterial species.
Rooting of tRNAome trees reveals conserved structures, indicating how the code was
shaped during evolution and suggesting a model for evolution of a LUCA tRNAome tree. We …