Figure 5.

Comparison of the observed number of amino acid replacements with that expected under neutrality (i.e., no selection) in human MRGX. The transmembrane, extracellular, and cytoplasmic domains are considered in A, B, and C, respectively. To obtain the number of amino acid replacements under neutral expectation, simulation was performed using sequence of the deduced MRGX progenitor (indicated in Fig. 1A) as the starting sequence (see Methods). Error bar represents one standard deviation of the simulated results.