Figure 1.

Probabilistic scheme for the identification of compensatory mutations based on amino acid (AA) sequences. The left panel shows the list of mixed AA unique sequences of the S-protein of all SARS-CoV-2 variants, which were then compared pairwise to create a binary population (BP) of the sequence, as shown in the middle panel (N = 1784, L = 1273, M = 1 590 436); “1” stands for the AA substitution, and “0” otherwise. The right panel illustrates how two mutation sites were compared using conditional probability over the S-binary population (BP). The mutation site i is compensatory to the site j or vice versa if both the conditional probability P(s_i|s_j) = 1 and P(s_j|s_i) =1.