Number of sites potentially under negative selection in the BTV genome according to two inference methods (FEL—fixed-effects likelihood, FUBAR—fast unconstrained Bayesian approximation).

1 Total number of codons in the alignment, with the actual number being variable among serotypes. Mean dN/dS were estimated using the ‘single likelihood ancestor counting’ (SLAC) method. Number of reassortment events were estimated relative to Seg-2, which itself was assessed for reassortment relative to Seg-6.