Journal of Molecular Evolution

, Volume 41, Issue 5, pp 539–548

The evolution of the type I interferon gene family in mammals

  • A. L. Hughes

DOI: 10.1007/BF00175811

Cite this article as:
Hughes, A.L. J Mol Evol (1995) 41: 539. doi:10.1007/BF00175811


A phylogenetic analysis of mammalian type I interferon (IFN) genes showed: (1) that the three main subfamilies of these genes in mammals (IFN-β, IFN-α, and IFN-ω) diverged after the divergence of birds and mammals but before radiation of the eutherian orders and (2) that IFN-β diverged first. Although apparent cases of interlocus recombination among mouse IFN-α genes were identified, the hypothesis that coding regions of IFN-α genes have been homogenized within species by interlocus recombination was not supported. Flanking regions as well as coding regions of IFN-α were more similar within human and mouse than between these species; and reconstruction of the pattern of nucleotide substitution in IFN-α coding regions of four mammalian species by the maximum parsimony method suggested that parallel substitutions have occurred far more frequently between species than within species. Therefore, it seems likely that IFN-α genes have duplicated independently within different eutherian orders. In general, type I IFN genes are subject to purifying selection, which in the case of IFN-α and IFN-β is strongest in the putative receptor-binding domains. However, analysis of the pattern of nucleotide substitution among IFN-ω genes suggested that positive Darwinian selection may have acted in some cases to diversify members of this subfamily at the amino acid level.

Key words

Type I interferon Mammals Interferon gene family 

Copyright information

© Springer-Verlag New York Inc 1995

Authors and Affiliations

  • A. L. Hughes
    • 1
  1. 1.Department of Biology and Institute of Molecular Evolutionary Genetics, 208 Mueller LaboratoryThe Pennsylvania State UniversityUniversity ParkUSA

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