Hybridization of Trna. Each tRNA was hybridized to every other (359), and grouped according to the specific amino acid encoded. Each bar represents the mean of 359 hybridizations. The mean ± SD of the 22 groups is indicated by the horizontal line. (Ini: initiation codon, Sec: termination codon. Amino acids are listed with their anticodons). Free energy estimates were determined using the Mfold and DINAMelt Web Servers [35, 56–58].