The clades I, II and III contain 114, 26, and 20 IFITM genes, respectively. All IFITM10 and IFITM5 genes are clustered in clades II and III, respectively. All other functional IFITM genes, including IFITM1, IFITM2, IFITM3, IFITM6 and IFITM7, are grouped in clade I, forming the biggest sub-family in the IFITM family. Because the expression of the IFITM genes in clade I can be induced by IFN and their functions are associated with immunity [8, 13, 15] , they are defined as immunity-related IFITM (IR-IFITM) sub-family.