Fig. 2

Spike (S) protein mutations detected in the Delta variant circulating in Uppsala County during 2021. The heatmap displays the relative abundance of different S protein amino acid substitutions/deletions (per week) from all the analysed Delta sequences (n = 1053). The intensity scale on the right indicates the percentage (%) of the sequences exhibiting that mutation (white = 0%; black = 100%). Y-axis shows the amino acid substitutions/deletions with the residue number corresponding to the S protein of the SARS-CoV-2 Wuhan-Hu-1 isolate (NCBI accession: NC_045512.2). The character before and after the residue number signify the wild type and substituted amino acids, respectively. The absence of a character after the residue number indicates an amino acid deletion. To reduce random sequencing errors, mutations detected in only one sequence during a week were omitted from that week. Signature mutations for the Delta variant are marked with an asterisk (*). R158G is not shown because it was not detected (https://gvn.org/covid-19/delta-b-1-617-2/ ).