Current address: Department of Biology, University College London, London WC1E 6BT, UK.
A tangled history: patterns of major histocompatibility complex evolution in the African mole-rats (Family: Bathyergidae)
Version of Record online: 5 JUL 2007
Biological Journal of the Linnean Society
Volume 91, Issue 3, pages 493–503, July 2007
How to Cite
KUNDU, S. and FAULKES, C. G. (2007), A tangled history: patterns of major histocompatibility complex evolution in the African mole-rats (Family: Bathyergidae). Biological Journal of the Linnean Society, 91: 493–503. doi: 10.1111/j.1095-8312.2007.00814.x
- Issue online: 5 JUL 2007
- Version of Record online: 5 JUL 2007
- Received 22 December 2005; accepted for publication 1 September 2006
- deep coalescence;
- DQα1 gene;
- positive selection;
- trans-species polymorphism
Phylogenetic trees based upon major histocompatibility complex (MHC) gene sequences, particularly those encompassing sites encoding the antigen recognition site, are often discordant with the species tree. It has been argued that the principal cause of such discordance is the presence of ancestrally derived polymorphisms persisting through speciation events as a consequence of selection. In the present study, we examine the evolution of the MHC class II DQα1 gene in an unusual family of hystricomorph rodents, the African mole-rats (Family: Bathyergidae). We show that there is a high level of trans-species polymorphism and that this is a result of positive selection. Furthermore, the major lineages of the gene tree are characterized by allelic motifs occurring in regions that coincide with the pocket domains of the putative antigen recognition site, a region that has been shown to be under positive selection in a number of MHC genes from a range of species. Finally, these alleles may have been retained for at least 48 million years. This is significantly older than the estimate for the equivalent primate locus and appears to be one of the oldest documented sets of MHC alleles. We suggest that these allelic motifs possess polymorphisms that have been immunologically important to African mole-rats over long periods of evolutionary history. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 493–503.