Immunogenetics

, Volume 54, Issue 5, pp 353–364

Evolution of the six horse IGHG genes and corresponding immunoglobulin gamma heavy chains

  • Bettina Wagner
  • Irene Greiser-Wilke
  • Anja K. Wege
  • Andreas Radbruch
  • Wolfgang Leibold
Original Paper

DOI: 10.1007/s00251-002-0458-4

Cite this article as:
Wagner, B., Greiser-Wilke, I., Wege, A.K. et al. Immunogenetics (2002) 54: 353. doi:10.1007/s00251-002-0458-4

Abstract.

It is generally assumed that the different mammalian IgG isotypes have developed during evolution by duplications of a common ancestor gamma heavy chain constant region gene (IGHG). In contrast to other species studied so far, which express between one and four IGHG genes, the horse (Equus caballus) genome contains six IGHG genes, and it has been postulated that they all can be expressed. For determination of the evolutionary history of the six horse IGHG genes, genomic DNA and cDNA of the IGHG genes were sequenced. The structure of these genes with reference to exons and introns was determined. Comparison of the deduced amino acid sequences of the horse IGHG genes revealed the greatest divergences in the hinge regions, and in the proximal CH2 domains. A phylogenetic comparison of the amino acid sequences of the six horse IGHG genes to those of other species shows that the horse IGHG genes form a distinct cluster. This indicates that the mammalian species included in this study probably share only one common ancestor IGHG gene with the horse. The six horse IGHG genes probably then evolved by gene duplication after species separation. In addition, various segmental exchanges were found between the horse IGHG genes, which might be the result of unequal crossing over and/or gene conversion events during the evolution of the six horse IGHG genes.

Equus caballus IGHG genes Horse immunoglobulin gamma heavy chains Horse IGHG evolution Segmental homology FcγR binding

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Bettina Wagner
    • 1
  • Irene Greiser-Wilke
    • 2
  • Anja K. Wege
    • 1
  • Andreas Radbruch
    • 3
  • Wolfgang Leibold
    • 1
  1. 1.Immunology Unit, School of Veterinary Medicine, Bischofsholer Damm 15, 30173 Hannover, Germany
  2. 2.Institute of Virology, School of Veterinary Medicine, Bünteweg 17, 30559 Hannover, Germany
  3. 3.German Rheumatism Research Center, Schumann Strasse 21/22, 10117 Berlin, Germany
  4. 4.Present address: James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Hungerford Hill Road, Ithaca, NY 14853, USA, e-mail: bw73@cornell.edu, Tel: +1-607-2565615, Fax: +1-607-2565608