Fig. 4. Substantial sharing of closely related strains within and between countries.

a, Number of sublineages found per country, classified by sublineage distribution (multi-country, black; private to one country, medium grey; singleton, light grey). b, Total high-quality genomes per country. c, Pairwise comparison of SNP distance distributions from samples in each country (with >1 sample), across all samples and within lineages. d, Minimum pairwise SNPs between samples from different countries. All pairwise SNP comparisons exclude comparisons with same samples. Haiti, South Africa and Mexico appear to be striking outliers in terms of genetic relatedness, but this reflects that the Haiti and Mexico samples were collected in the 1950s, and we had only a single genome from these countries.