Evolution of Interferon Genes

Abstract

Interferon genes are particularly interesting from an evolutionary viewpoint because they are multiple gene families from which are emerging data relevant to several levels of biologic organization: DNA structure, protein function, varied and complex biologic processes. Presently, we recognize three interferon gene families: α, β, and γ — leukocyte, fibroblast, and immune interferon, respectively. Interferons-α and -β have been examined at the DNA level; interferon-γ has not. DNA studies suggest that human interferon-α is coded by at least ten genes (Nagata et al. 1980; Goeddel et al. 1981). DNA studies suggest that interferon-β is coded by only one gene(Tavernier et al. 1981; Houghton et al. 1981; Lawn et al. 198 la), but less direct evidence indicates the existence of more than one human interferon-β gene (Sagar et al. 1981). Therefore, while interferon genes are multiple gene families, the number of genes is not the same for the different types of interferon and may differ for the same type from different mammals. The latter conclusion would of course imply that recent alterations have taken place in the interferon gene families.