Annotated IFITM genes were retrieved from Ensembl databases (http://www.ensembl.org/). To identify additional putative IFITM functional genes and pseudogenes, tBLASTn searches were performed in Ensembl using human IFITM1, IFITM2, IFITM3 and IFITM5 as queries against the available genome sequences of species listed in Table 1 with E value,10 25 [62] . After deleting the redundancies and merging overlapping sequences, the remained sequences with.150 nt were analyzed by GENSCAN to identify the putative coding sequence. Each candidate IFITM gene was used as a query to BLAST against GenBank non-redundant protein database to make sure the best hit is an IFITM gene. The exons and intron of the remained sequences were detected with GeneWise. The presences of CD225 domain and C-terminal TMD in candidate sequences were identified using the online tools SMART (http://smart.emblheidelberg.de) and SOSUI (http://bp.nuap.nagoya-u.ac.jp/sosui/ ), respectively. If the sequence did not have complete CD225 domain and the C-terminal TMD, or its open reading frame (ORF) was disrupted, this sequence was regarded as a pseudogene. To avoid the possible error in pseudogene identification, the PSEDOPIPE approach (http://pseudofam.pseudogene.org/ pages/main/about.jsf) [63] was further used to confirm identified IFITM pseudogenes. On the other hand, because authentic IFITM proteins are in a range of 102 to 157 amino acids [2] , the candidates that are outside above range and have complete open reading frame, complete CD225 domain and the C-terminal TMD were identified as functional genes and referred to as IFITM-like genes.