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Journal of Molecular Evolution

, Volume 48, Issue 6, pp 663–674 | Cite as

Evolution of Mhc–DRB Introns: Implications for the Origin of Primates

  • Heike  Kupfermann
  • Yoko  Satta
  • Naoyuki  Takahata
  • Herbert  Tichy
  • Jan  Klein

Abstract.

Introns are generally believed to evolve too rapidly and too erratically to be of much use in phylogenetic reconstructions. Few phylogenetically informative intron sequences are available, however, to ascertain the validity of this supposition. In the present study the supposition was tested on the example of the mammalian class II major histocompatibility complex (Mhc) genes of the DRB family. Since the Mhc genes evolve under balancing selection and are believed to recombine or rearrange frequently, the evolution of their introns could be expected to be particularly rapid and subject to scrambling. Sequences of intron 4 and 5 DRB genes were obtained from polymerase chain reaction-amplified fragments of genomic DNA from representatives of six eutherian orders—Primates, Scandentia, Chiroptera, Dermoptera, Lagomorpha, and Insectivora. Although short stretches of the introns have indeed proved to be unalignable, the bulk of the intron sequences from all six orders, spanning >85 million years (my) of evolution, could be aligned and used in a study of the tempo and mode of intron evolution. The analysis has revealed the Mhc introns to evolve at a rate similar to that of other genes and of synonymous sites of non-Mhc genes. No evidence of homogenization or large-scale scrambling of the intron sequences could be found. The Mhc introns apparently evolve largely by point mutations and insertions/deletions. The phylogenetic signals contained in the intron sequences could be used to identify Scandentia as the sister group of Primates, to support the existence of the Archonta superorder, and to confirm the monophyly of the Chiroptera.

Key words: Major histocompatibility complex (Mhc) — Intron evolution — Primate origin — Mammalian evolution — Scandentia — Chiroptera —DRB genes 

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Copyright information

© Springer-Verlag New York Inc. 1999

Authors and Affiliations

  • Heike  Kupfermann
    • 1
  • Yoko  Satta
    • 2
  • Naoyuki  Takahata
    • 2
  • Herbert  Tichy
    • 1
  • Jan  Klein
    • 1
  1. 1.Max-Planck-Institut für Biologie, Abteilung Immungenetik, Corrensstrasse 42, 72076 Tübingen, GermanyDE
  2. 2.The Graduate University for Advanced Studies, Department of Biosystems Science, Hayama, 240-0193 Kanagawa, JapanJP

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