Though it took several years, Nirenberg and others deciphered the meaning of all 64 triplet codons. Nirenberg and Matthaei kept track of the progress on this 15" x 48" chart pieced together from ...

Each tRNA reads at the ribosome a genetic code for the that specific amino acid. Crick suggested that a single tRNA would have to read more than one code since we have 40 tRNAs and 61 codes ...