title: Diversity of MHC DQB and DRB Genes in the Endangered Australian Sea Lion (Neophoca cinerea).
abstract: Major histocompatibility complex (MHC) class II molecules have an important role in vertebrate adaptive immunity, being responsible for recognizing, binding, and presenting specific antigenic peptides to T lymphocytes. Here, we study the MHC class II DQB and DRB exon 2 genes of the Australian sea lion (Neophoca cinerea), an endangered pinniped species that experiences high pup mortality. Following characterization of N. cinerea DQB and DRB by molecular cloning, and evaluation of diversity in pups across 2 colonies using variant screening (n = 47), 3 DQB alleles and 10 DRB variants (including 1 pseudogene allele) were identified. The higher diversity at DRB relative to DQB is consistent with other studies in marine mammals. Despite overall lower MHC class II allelic diversity relative to some other pinniped species, we observed similar levels of nucleotide diversity and selection in N. cinerea. In addition, we provide support for recent divergence of MHC class II alleles. The characterization of MHC class II diversity in the Australian sea lion establishes a baseline for further investigation of associations with disease, including endemic hookworm infection, and contributes to the conservation management of this species.
authors.affiliation: From the Faculty of Veterinary Science, The University of Sydney, B14 McMaster Building, Camperdown, New South Wales 2006, Australia.
authors.forename: Quintin
authors.initials: Q
authors.lastname: Lau
authors.affiliation: From the Faculty of Veterinary Science, The University of Sydney, B14 McMaster Building, Camperdown, New South Wales 2006, Australia.
authors.forename: Natalie
authors.initials: N
authors.lastname: Chow
authors.affiliation: From the Faculty of Veterinary Science, The University of Sydney, B14 McMaster Building, Camperdown, New South Wales 2006, Australia.
authors.forename: Rachael
authors.initials: R
authors.lastname: Gray
authors.affiliation: From the Faculty of Veterinary Science, The University of Sydney, B14 McMaster Building, Camperdown, New South Wales 2006, Australia.
authors.forename: Jaime
authors.initials: J
authors.lastname: Gongora
authors.affiliation: From the Faculty of Veterinary Science, The University of Sydney, B14 McMaster Building, Camperdown, New South Wales 2006, Australia. damien.higgins@sydney.edu.au.
authors.forename: Damien P
authors.initials: DP
authors.lastname: Higgins
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001315:Australia; D056727:Endangered Species; D005091:Exons; D005802:Genes, MHC Class II; D014644:Genetic Variation; D059866:HLA-DQ beta-Chains / Q000235:genetics; D059806:HLA-DR beta-Chains / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D046070:Sea Lions / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D059866:HLA-DQ beta-Chains; D059806:HLA-DR beta-Chains
keywords: Australian sea lion; MHC; hookworm; pinnipeds