title: Evolution of new tRNA-synthetase classes.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases; D001483:Base Sequence; D005075:Biological Evolution; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D013914:Threonine-tRNA Ligase
chemical_list: D000604:Amino Acyl-tRNA Synthetases; D013914:Threonine-tRNA Ligase