In the phylogenetic tree, IR-IFITM, IFITM5 and IFITM10 genes from different species form three independent clusters. We investigated type I functional divergence among IR-IFITM, IFITM5 and IFITM10 using Diverge v2.0 with the Maximum-Likelihood Estimation (MLE) and Model-Free Method (MFE) [32] . Type I sites represent amino acids conservation in one cluster, but high variability in another, suggesting that these residues have been subjected to different functional constraints. The coefficient of functional divergence, h, ranging from 0 to 1, was used to test the statistical significance of functional divergence that has occurred between different clusters. A null hypothesis of h = 0 indicates that the evolutionary rate is virtually the same between two clusters at each site. When h.0.5, the null hypothesis is considered to be significantly rejected. The important amino acid residues most likely to be responsible for functional divergence were then predicted by calculating the site-specific profile based on posterior analysis for all pairs of clusters with functional divergence. Figure S2 Sequence alignment of the vertebrate IFITM5 genes. Alignment was used to reconstruct the Bayesian tree in Figure 2B . (PDF) Figure S3 Sequence alignment of the vertebrate IFITM10 genes. Alignment was used to reconstruct the Bayesian tree in Figure 2C . (PDF) Figure S4 Sequence alignment of the mammalian IR-IFITM genes. Alignment was used to reconstruct the phylogenetic trees shown in Figure 3 . The abbreviations were adopted from the species names in Table 1  Filovirus Research in Gabon and Equatorial Africa: The Experience of a Research Center in the Heart of Africa Health research programs targeting the population of Gabon and Equatorial Africa at the International Center for Medical Research in Franceville (CIRMF), Gabon, have evolved during the years since its inception in 1979 in accordance with emerging diseases. Since the reemergence of Ebola virus in Central Africa, the CIRMF “Emerging Viral Disease Unit” developed diagnostic tools and epidemiologic strategies and transfers of such technology to support the response of the National Public Health System and the World Health Organization to epidemics of Ebola virus disease. The Unit carries out a unique investigation program on the natural history of the filoviruses, emergence of epidemics, and Ebola virus pathogenesis. In addition, academic training is provided at all levels to regional and international students covering emerging conditions (host factors, molecular biology, genetics) that favor the spread of viral diseases. The International Centre for Medical Researches of Franceville (CIRMF) was founded in 1974 by His Excellency El Hadj Omar Bongo Ondimba, President of the Gabonese Republic, and Mr. Pierre Guillaumat, the chairman of the petroleum company, Total Gabon. The Centre was inaugurated on December 5th, 1979 with the participation of numerous internationally eminent scientists (Figure 1) . In the 1990s, viral hemorrhagic fevers became a focus of attention in Equatorial. The decision to develop a high security laboratory for the study of Ebola virus disease came after a 1996 Ebola virus disease outbreak in Mayibout area, Gabon. The main objective was to develop the potential for rapid and specific diagnosis on viral hemorrhagic fevers and to have a backup for field investigation of severe viral hemorrhagic fever epidemics. Because the unique expertise and interaction of the CIRMF team along with the international World Health Organization (WHO) teams for Ebola virus disease, the Gabonese government agreed to such a project. The first BSL3+ (including negative pressure and glove box) laboratory was built in 1997, mostly financed by the Foreign Ministry of France ( Figure 2 ). This laboratory was built in a period of quasi "emergence" of successive Ebola virus disease outbreaks in Gabon, and the plans to upgrade the BSL3+ laboratory were not efficient. A specific research unit was founded in 1998 to study emerging infectious diseases: The Emerging Viral Disease Unit (UMVE). Thanks to work done between 1996 and 1998, both in the field and in research, CIRMF became a National Reference Laboratory and a WHO Collaborating Center in the Equatorial African region. A second high security laboratory for Risk Group 3/4 Agents, mostly funded by the TOTAL Gabon oil company and the Gabonese Government, was built between 2003 and 2008 on CIRMF campus ( Figure 3 ). This BSL-4 laboratory was commissioned by a combined team of experts from the Pasteur Institute of Paris, National Institute of Health and Medical Research, France, and Jean Mérieux P4 laboratory of Lyon. 