To confirm the results from PAML, similar positive selection analyses were performed using MEME on the DATAMONKEY server. The results reveal that there are five, four, seven and one sites underwent significant positive selection in primate, rodent, marmoset IR-IFITM groups and frog IFITM10 group, respectively (Table S4) . PSSs identified by MEME method are consistent with those identified by PAML. Furthermore, positive selection can be also confirmed by branch-site REL method in both IR-IFITM and IFITM10 clades (Fig. S7) . The major lineages that have undergone positive selection in the IR-IFITM clade are primate and rodent (Fig. S7A) . Additionally, IFITM10 in lower vertebrate lineages also experienced strong selective pressure. Positively selected branches were detected in both teleost and frog lineages (Fig. S7B ).