2.6. Selective pressure analysis
Selective pressure analysis was performed using MEME in Hyphyv.2.5.6. 213 Omicron and 139 Delta sequences (nsp3, nsp5, nsp12, and Spike genes) were subjected to selective pressure analysis. Each dataset was first aligned using Neighbor-Joining (NJ) algorithm with 1,000 bootstraps using Maximum Composite Likelihood Model. The aligned sequences were analyzed using Hyphy and the results were visualized using HyPhy Vision (http://vision.hyphy.org/).p-value lower than 0.1 was considered as significant.