Calculated TMRCA values for ORF2.N and ORF1.

The values for the time to the most recent common ancestor were calculated using BEAST using the expanded sequence data set (See table S1). These values are calculated using a strict clock, an uncorrelated lognormal relaxed clock and an uncorrelated exponential relaxed clock with a coalescent constant size tree prior. The mean time and limits of the 95% highest posterior probability density are shown for each ancestor. The genotypes column shows which genotypes belong to each ancestor. Where no values are listed for the genotype 3 & 4 ancestor for the uncorrelated exponential relaxed clock this is because genotypes 3 and 4 do not share a common ancestor in this model. The bold text values denote models for which some variables have an ESS below 200.