Fig. 4

Bayesian phylogenetic analysis of 19F ST271 in China. To reduce the error from various sources, we used only the genomes of 19F ST271 (n = 301) from our collection. a Time-scaled phylogeny of 301 19F ST271 genomes. Nodes of the respective tMRCA (the most recent common ancestor) of 19F ST271-A and 19F ST271-B are marked with circle and triangle, respectively. The pink strip on each node represents a 95% confidence interval derived from highest posterior density (HPD) analysis for its differentiation time, corresponding to the timeline at the bottom of the figure. Clade of 19F ST271-B (n = 289) is collapsed and represented by blue-shaded triangle. b Bayesian skyline plot of genetic diversity shows sharp expansion of 19F ST271 during the 1990s. The vertical axis shows the estimated effective population size at the corresponding time. The shaded blue areas on either side of the line represent 95% HPD confidence intervals