Figure 4

Distributions of random code costs obtained by permutation of amino acid assignments to the supercodons without question marks in Fig. 2. The green line shows the cost of the code from Fig. 1, and the red line shows the mean of the distribution. (a) 9 amino acids from Fig. 2a are used, the distance from the mean to the red line is 2.2 standard deviations; (b) Ser is added to the list of the 9 amino acids, the distance from the mean to the red line is 2.5 standard deviations.