Immunogenetics

, 60:423

Evolution of major histocompatibility complex by “en bloc” duplication before mammalian radiation

  • Elodie Darbo
  • Etienne G. J. Danchin
  • Michael F. P. Mc Dermott
  • Pierre Pontarotti
Original Paper

Abstract

Duplications are an important mechanism for the emergence of genetic novelties. Reports on duplicated genes are numerous, and mechanisms for polyploidization or local gene duplication are beginning to be understood. When a local duplication is studied, searches are usually done gene-by-gene, and the size of duplicated segments is not often investigated. Therefore, we do not know if the gene in question has duplicated alone or with other genes, implying that “en bloc” duplications are poorly studied. We propose a method for identification of “en bloc” duplication using mapping, phylogenetic and statistical analyses. We show that two segments present in the major histocompatibility complex (MHC) region of human chromosome 6 have resulted from an “en bloc” duplication that took place between divergence of amniotes and methaterian/eutherian separation. These segments contain members of the same multigenic families, namely olfactory receptors genes, genes encoding proteins containing B30.2 domain, genes encoding proteins containing immunoglobulin V domain and MHC class I genes. We will discuss the fact that olfactory receptors and MHC genes have undergone positive selection, which could have helped in fixation of the surrounding genes.

Keywords

Evolution “En bloc” duplication MHC Phylogeny Hitchhiking effect 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Elodie Darbo
    • 1
  • Etienne G. J. Danchin
    • 2
  • Michael F. P. Mc Dermott
    • 3
  • Pierre Pontarotti
    • 1
  1. 1.LATP UMR 6632 CNRS Evolution biologique et ModélisationUniversité de ProvenceMarseille Cedex 03France
  2. 2.UMR IBSV, INRA, UNSA, CNRSCentre de recherche de Sophia-AntipolisSophia-Antipolis CedexFrance
  3. 3.Leeds Institute of Molecular Medicine (LIMM), Wellcome Trust Brenner BuildingSt. James’s University HospitalLeedsUK

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