In total, 20 IFITM5 genes were identified in 20 vertebrates, covering species from teleosts to eutherians (Fig. 2B ). No IFITM5 gene was identified in gorilla, marmoset, tree shrew, rabbit, dog, fugu, or medaka. Due to low sequencing coverage, we cannot rule out the possibility that the lack of IFITM5 in these genomes should be ascribed to relatively low quality of the genome sequences. The phylogenetic relationships of the available IFITM5 genes are consistent with the known species phylogeny. Only one IFITM5 gene was identified in each species, indicating that no gene duplication occurred in IFITM5 gene during the evolution of vertebrates.