Fig. 3From: Pango lineage designation and assignment using SARS-CoV-2 spike gene nucleotide sequencesHistogram of the proportion of spike protein nucleotide sites that are ambiguous (i.e. contain at least one IUPAC ambiguity code). The distribution is calculated for all SARS-CoV-2 sequences in GISAID that (i) have been designated to a Pango lineage, and (ii) have N at < 5% of sites across the whole genome, excluding UTRsBack to article page