title: Evolution of MHC class I genes in the endangered loggerhead sea turtle (Caretta caretta) revealed by 454 amplicon sequencing.
abstract: BACKGROUND
  In evolutionary and conservation biology, parasitism is often highlighted as a major selective pressure. To fight against parasites and pathogens, genetic diversity of the immune genes of the major histocompatibility complex (MHC) are particularly important. However, the extensive degree of polymorphism observed in these genes makes it difficult to conduct thorough population screenings.
  
  
  METHODS
  We utilized a genotyping protocol that uses 454 amplicon sequencing to characterize the MHC class I in the endangered loggerhead sea turtle (Caretta caretta) and to investigate their evolution at multiple relevant levels of organization.
  
  
  RESULTS
  MHC class I genes revealed signatures of trans-species polymorphism across several reptile species. In the studied loggerhead turtle individuals, it results in the maintenance of two ancient allelic lineages. We also found that individuals carrying an intermediate number of MHC class I alleles are larger than those with either a low or high number of alleles.
  
  
  CONCLUSIONS
  Multiple modes of evolution seem to maintain MHC diversity in the loggerhead turtles, with relatively high polymorphism for an endangered species.
authors.affiliation: Department of Evolutionary Ecology of Marine Fishes, GEOMAR|Helmholtz Center for Ocean Research, Kiel, 24105, Germany.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Stiebens
authors.forename: Sonia E
authors.initials: SE
authors.lastname: Merino
authors.forename: Frédéric J J
authors.initials: FJ
authors.lastname: Chain
authors.forename: Christophe
authors.initials: C
authors.lastname: Eizaguirre
mesh_terms: D000818:Animals; D056727:Endangered Species; D019143:Evolution, Molecular; D005805:Genes, MHC Class I; D014644:Genetic Variation; D005838:Genotype; D010802:Phylogeny; D030162:Reptilian Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014426:Turtles / Q000145:classification / Q000235:genetics*
chemical_list: D030162:Reptilian Proteins