Figure 1From: Adaptive evolution of bat dipeptidyl peptidase 4 (dpp4): implications for the origin and emergence of Middle East respiratory syndrome coronavirusSelection pressures on DPP4 during mammalian evolution. Ratios of nonsynonymous (dN) to synonymous (dS) nucleotide substitutions per site (dN/dS) are shown on four major ancestral branches; dN and dS numbers are also given in parentheses. Values for individual lineages are given in Table 2. DPP4 sequences of bat origin are shaded.Back to article page