title: Extensive Allelic Diversity of MHC Class I in Wild Mallard Ducks.
abstract: MHC class I is critically involved in defense against viruses, and diversity from polygeny and polymorphism contributes to the breadth of the immune response and health of the population. In this article, we examine MHC class I diversity in wild mallard ducks, the natural host and reservoir of influenza A viruses. We previously showed domestic ducks predominantly use UAA, one of five MHC class I genes, but whether biased expression is also true for wild mallards is unknown. Using RT-PCR from blood, we examined expressed MHC class I alleles from 38 wild mallards (Anas platyrhynchos) and identified 61 unique alleles, typically 1 or 2 expressed alleles in each individual. To determine whether expressed alleles correspond to UAA adjacent to TAP2 as in domestic ducks, we cloned and sequenced genomic UAA-TAP2 fragments from all mallards, which matched transcripts recovered and allowed us to assign most alleles as UAA Allelic differences are primarily located in α1 and α2 domains in the residues known to interact with peptide in mammalian MHC class I, suggesting the diversity is functional. Most UAA alleles have unique residues in the cleft predicting distinct specificity; however, six alleles have an unusual conserved cleft with two cysteine residues. Residues that influence peptide-loading properties and tapasin involvement in chicken are fixed in duck alleles and suggest tapasin independence. Biased expression of one MHC class I gene may make viral escape within an individual easy, but high diversity in the population places continual pressure on the virus in the reservoir species.
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Ximena
authors.identifier: 0000-0003-0986-3999
authors.initials: X
authors.lastname: Fleming-Canepa
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Shawna M
authors.initials: SM
authors.lastname: Jensen
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Mesa
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Laura
authors.identifier: 0000-0003-0267-1070
authors.initials: L
authors.lastname: Diaz-Satizabal
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Alexa J
authors.initials: AJ
authors.lastname: Roth
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Julie A
authors.identifier: 0000-0001-8091-8249
authors.initials: JA
authors.lastname: Parks-Dely
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Moon
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Janet P
authors.initials: JP
authors.lastname: Wong
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Danyel
authors.identifier: 0000-0002-0371-4987
authors.initials: D
authors.lastname: Evseev
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: Desolie A
authors.initials: DA
authors.lastname: Gossen
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: David G
authors.identifier: 0000-0002-4301-8134
authors.initials: DG
authors.lastname: Tetrault
authors.affiliation: Department of Biological Sciences and the Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada kmagor@ualberta.ca.
authors.forename: Katharine E
authors.identifier: 0000-0002-9331-1486
authors.initials: KE
authors.lastname: Magor
mesh_terms: D000483:Alleles; D000818:Animals; D004372:Ducks / Q000235:genetics* / Q000276:immunology*; D005805:Genes, MHC Class I / Q000235:genetics* / Q000276:immunology*; D005838:Genotype; D011110:Polymorphism, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction