Fig. 1

Evolutionary analysis based on angiotensin-converting enzyme 2 (ACE2). a Phylogenetic tree included 34 amino acid sequences. The species in blue represent the known severe acute respiratory syndrome coronavirus (SARS-CoV)-2 hosts, the species in gray represent the known MERS-CoV host, and the species in red represent the known SARS-CoV hosts. The numbers in the phylogenetic tree represent the posterior probability that are the confidence values from each clade (the higher confidence is 1). Scale bar indicates the number of substitutions/site for the trees. b Bayesian phylogenetic tree was based on ACE2 protein. ACE2 protein sequences were aligned and used to infer the evolutionary divergence values, represented in the matrix heatmap. The heatmap color gradient represents the evolutionary divergence based on the number of amino acid substitutions/site from a pairwise comparison between sequences, from low (red) to high (blue). Evolutionary divergence analyses were conducted using the JTT matrix-based model. The heatmap were constructed using the Microsoft Excel™ software