Figure 1.

(a) Maximum likelihood (ML) phylogenetic tree used for TempEst analysis (panel (a)) inferred under a Kimura 2-parameter model with invariable sites. Stars at tree nodes indicate nodes with bootstrap values greater than 80%. Letters to the right and branch colors indicate enterovirus 71 (EV71) genotypes. TempEst analysis of the temporal population structure in the total EV-A71 alignment with 16 BrCr-like Chinese sequences, midpoint tree root (b), the sole genotype A (16 Chinese sequences and 4 prototype BrCr sequences), best-fitting tree root (c), and the sole genotype C, represented by 55 sequences (d). White circles in panel (b) correspond to genotype A sequences (prototype strain sequence JN874547 and Chinese sequences), and grey circles correspond to the sequences of other genotypes. The correlation coefficient, R², and substitution rate (regression line slope) are indicated in each plot.