Evolution of MHC class I genes in the European badger (Meles meles)Sin, Y. W., Dugdale, H. L., Newman, C., Macdonald, D. W. & Burke, T., Jul-2012, In : Ecology and Evolution. 2, 7, p. 1644-1662 19 p.
Research output: Contribution to journal › Article › Academic › peer-review
The major histocompatibility complex (MHC) plays a central role in the adaptive immune system and provides a good model with which to understand the evolutionary processes underlying functional genes. Trans-species polymorphism and orthology are both commonly found in MHC genes; however, mammalian MHC class I genes tend to cluster by species. Concerted evolution has the potential to homogenize different loci, whereas birth-and-death evolution can lead to the loss of orthologs; both processes result in monophyletic groups within species. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. We present the first study of MHC class I genes in a species from the superfamily Musteloidea. The European badger (Meles meles) exhibits moderate variation in MHC class I sequences when compared to other carnivores. We identified seven putatively functional sequences and nine pseudogenes from genomic (gDNA) and complementary (cDNA) DNA, signifying at least two functional class I loci. We found evidence for separate evolutionary histories of the alpha 1 and alpha 2/alpha 3 domains. In the alpha 1 domain, several sequences from different species were more closely related to each other than to sequences from the same species, resembling orthology or trans-species polymorphism. Balancing selection and probable recombination maintain genetic diversity in the alpha 1 domain, evidenced by the detection of positive selection and a recombination event. By comparison, two recombination breakpoints indicate that the alpha 2/alpha 3 domains have most likely undergone concerted evolution, where recombination has homogenized the alpha 2/alpha 3 domains between genes, leading to species-specific clusters of sequences. Our findings highlight the importance of analyzing MHC domains separately.
|Number of pages||19|
|Journal||Ecology and Evolution|
|Publication status||Published - Jul-2012|
- Balancing selection, birth-and-death evolution, concerted evolution, major histocompatibility complex, orthology, trans-species polymorphism, MAJOR HISTOCOMPATIBILITY COMPLEX, AMINO-ACID SITES, MYCOBACTERIUM-BOVIS, EURASIAN BADGERS, TRANSSPECIES POLYMORPHISM, MOLECULAR PHYLOGENY, CONCERTED EVOLUTION, POPULATION-DYNAMICS, CARNIVORA MAMMALIA, POSITIVE SELECTION