Genomic Analysis of SARS-CoV-2 Alpha, Beta and Delta Variants of Concern Uncovers Signatures of Neutral and Non-Neutral Evolution. A correction has been made to Materials and Methods, SFS under Birth-and-Death Process Model with Mutation and Selection, paragraph 1: Under these hypotheses, if the fitnesses of the two types are SB 0 sb < SB 1 sb , then the site frequency spectrum approximately follows the power curve, in our notation (6) HT ht hence the tail I T i ( I x i ) = I i SB I i > I x i sb I S i ( I i ) follows the law (7) HT ht where I i = I i SB 0 sb / I i SB 1 sb . However, this is inconsistent with the original notation HT ht . [Extracted from the article]