Immunogenetics

, Volume 60, Issue 5, pp 219–231

Support for the minimal essential MHC hypothesis: a parrot with a single, highly polymorphic MHC class II B gene

  • Colin R. Hughes
  • Shana Miles
  • Jaclyn M. Walbroehl
Original Paper

DOI: 10.1007/s00251-008-0287-1

Cite this article as:
Hughes, C.R., Miles, S. & Walbroehl, J.M. Immunogenetics (2008) 60: 219. doi:10.1007/s00251-008-0287-1

Abstract

We characterized the MHC class II B gene in the green-rumped parrotlet, Forpus passerinus. Three approaches were used: polymerase chain reaction amplification using primers complementary to conserved regions of exon 2, sequencing clones from a genomic library, and amplification of exon 2 using species-specific primers. All three methods indicate that there is only a single class II B locus in this species and no pseudogenes. We suggest that this is the ancestral state for birds. The gene is highly polymorphic; 33 alleles were found in a sample of 25 individuals. Variation in exon 2 is concentrated in the peptide binding residues which show a significant excess of non-synonymous substitutions consistent with the operation of selection in maintaining this extraordinary polymorphism. Genomic clones show that major histocompatibility complex (MHC) gene organization is different from that of chickens; the class II A locus is close to II B. These data provide support for the hypothesis that the bird MHC constitutes a “minimal essential MHC” for responding to infectious disease.

Keywords

MHC class IIEvolutionParrotAllelesPolymorphic

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Colin R. Hughes
    • 1
  • Shana Miles
    • 2
  • Jaclyn M. Walbroehl
    • 1
  1. 1.Department of Biological SciencesFlorida Atlantic UniversityDavieUSA
  2. 2.Department of Microbiology and ImmunologyUniformed Services UniversityBethesdaUSA