title: Genetic variation of the major histocompatibility complex (MHC class II B gene) in the threatened Hume's pheasant, Syrmaticus humiae.
abstract: Major histocompatibility complex (MHC) genes are the most polymorphic genes in vertebrates and encode molecules that play a crucial role in pathogen resistance. As a result of their diversity, they have received much attention in the fields of evolutionary and conservation biology. Here, we described the genetic variation of MHC class II B (MHCIIB) exon 2 in a wild population of Hume's pheasant (Syrmaticus humiae), which has suffered a dramatic decline in population over the last three decades across its ranges in the face of heavy exploitation and habitat loss. Twenty-four distinct alleles were found in 73 S. humiae specimens. We found seven shared alleles among four geographical groups as well as six rare MHCIIB alleles. Most individuals displayed between one to five alleles, suggesting that there are at least three MHCIIB loci of the Hume's pheasant. The dN ⁄ dS ratio at putative antigen-binding sites (ABS) was significantly greater than one, indicating balancing selection is acting on MHCIIB exon 2. Additionally, recombination and gene conversion contributed to generating MHCIIB diversity in the Hume's pheasant. One to three recombination events and seventy-five significant gene conversion events were observed within the Hume's pheasant MHCIIB loci. The phylogenetic tree and network analysis revealed that the Hume's pheasant alleles do not cluster together, but are scattered through the tree or network indicating a trans-species evolutionary mode. These findings revealed the evolution of the Hume's pheasant MHC after suffering extreme habitat fragmentation.
authors: Natural History Museum of Guangxi, Nanning 530012, People's Republic of China.
authors: Weicai
authors: W
authors: Chen
authors: College of Life Science and Technology, Yulin Normal University, Yulin 537000, People's Republic of China.
authors: Yongjian
authors: Y
authors: Bei
authors: Guangxi Key Laboratory of Rare and Endangered Animal Ecology, College of Life Sciences Guangxi Normal University, Guilin 541004, People's Republic of China.
authors: Hanhua
authors: H
authors: Li
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002681:China; D005091:Exons; D046094:Galliformes / Q000145:classification / Q000235:genetics*; D005785:Gene Conversion; D005802:Genes, MHC Class II; D014644:Genetic Variation; D005843:Geography; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D012641:Selection, Genetic; D016415:Sequence Alignment; D013045:Species Specificity
references: PLoS One. 2013 Jul 23;8(7):e69135
references: 23935938
references: Scand J Immunol. 1998 Mar;47(3):199-209
references: 9519857
references: Mol Biol Evol. 2006 Feb;23(2):254-67
references: 16221896
references: Nature. 1975 Jul 3;256(5512):50-2
references: 1079575
references: Mol Biol Evol. 2011 Oct;28(10):2731-9
references: 21546353
references: J Mol Evol. 1998 Jun;46(6):633-8
references: 9608045
references: Immunogenetics. 2008 May;60(5):233-47
references: 18389232
references: Mol Biol Evol. 1999 Apr;16(4):479-90
references: 10331274
references: Immunol Rev. 1995 Feb;143:63-88
references: 7558083
references: Immunogenetics. 1990;31(4):217-9
references: 2329006
references: J Evol Biol. 2009 Jun;22(6):1284-94
references: 19453370
references: J Mol Evol. 1995 Aug;41(2):115-9
references: 7666440
references: Syst Biol. 2008 Oct;57(5):758-71
references: 18853362
references: J Mol Evol. 2007 Nov;65(5):541-54
references: 17925996
references: Immunogenetics. 2011 Nov;63(11):753-71
references: 21710346
references: Genetics. 1997 Feb;145(2):421-33
references: 9071595
references: Bioinformatics. 2009 Jun 1;25(11):1451-2
references: 19346325
references: Genetica. 2010 Feb;138(2):265-71
references: 19851875
references: Nature. 1993 Jul 1;364(6432):33-9
references: 8316295
references: Evolution. 2003 Aug;57(8):1707-22
references: 14503614
references: Mol Biol Evol. 2007 Aug;24(8):1586-91
references: 17483113
references: Ecol Evol. 2014 Mar;4(6):688-98
references: 24683452
references: Chemosphere. 2011 Oct;85(3):494-501
references: 21880349
references: BMC Genomics. 2006 Dec 21;7:322
references: 17184537
references: Heredity (Edinb). 2006 Jan;96(1):7-21
references: 16094301
references: J Evol Biol. 2011 Sep;24(9):1847-56
references: 21605219
references: Immunogenetics. 2002 Aug;54(5):348-52
references: 12185538
references: Bioinformatics. 2010 Oct 1;26(19):2462-3
references: 20798170
references: Nucleic Acids Res. 2003 Jan 1;31(1):311-4
references: 12520010
references: Mol Biol Evol. 1986 Sep;3(5):418-26
references: 3444411
references: Mol Biol Evol. 2004 Feb;21(2):255-65
references: 14660700
references: Mol Biol Evol. 2005 Apr;22(4):1107-18
references: 15689528
references: Mol Ecol. 2001 Jun;10(6):1399-412
references: 11412363
references: J Hered. 2012 May-Jun;103(3):371-9
references: 22268162
references: J Immunol. 2004 Jun 1;172(11):6751-63
references: 15153492
references: Immunogenetics. 2007 Sep;59(9):725-34
references: 17653538