摘要
主要组织相容性复合体(major histocompatibility complex,MHC)是脊椎动物重要的功能基因家族之一,其所编码的MHC分子具有维持机体世代适应环境变化的能力和功能,是研究动物适应性进化研究的最佳遗传标记。本研究选择青藏高原的主要畜种资源——藏绵羊(Ovis aries)为研究对象,利用聚合酶链式反应-单链构象多态(polymerase chain reaction-single strand conformation polymorphism,PCRSSCP)技术对甘肃(欧拉,乔科和甘加型)和青海(青海欧拉型和青海高原型)的5个藏绵羊生态群体的DQA座位基因遗传特征进行研究,以期揭示其与藏绵羊高原适应性进化的机制;结果在藏绵羊DQA座位的2个基因中发现了33个等位基因和125个核苷酸变异位点,表明5个生态群体藏绵羊的DQA座位基因均具有丰富的多态性;分析证明平衡选择是维持藏绵羊DQA座位基因多态性的主要机制之一,甘肃和青海5个藏绵羊生态群体DQA座位基因区域之间的变化(among groups)小于同一区域不同群体间的变化(among population with groups),进一步说明藏绵羊DQA座位基因发生了正选择作用和适应性进化。研究结果将为藏绵羊的遗传改良和种质创新提供基础数据。
Major histocompatibility complex(MHC), one of the vital functional gene families in vertebrates,encodes MHC molecule which has the function and ability to maintain the organism adapt to environmental changes from generation to generation, and is the best genetic marker for investigating adaptive evolution in animals. Tibetan sheep(Ovis aries), the main livestock resources in Qinghai- Tibetan plateau, was chosen as research object, and the genetic characteristics of DQA genes in 5 ecological Tibetan sheep populations from Gansu(Oula, Qiaoke and Ganjia type) and Qinghai(Oula and plateau type) were investigated using polymerase chain reaction- single strand conformation polymorphism(PCR- SSCP) techniques in this study,which aimed to reveal its adaptive evolutionary mechanism in plateau Tibetan sheep. The results showed that33 alleles and 125 SNPs were discovered in 2 genes of Tibetan sheep DQA locus. This indicated that the DQA genes in 5 ecological Tibetan sheep populations exhibited abundant polymorphism. Subsequent analysis demonstrated that balancing selection was one of the mechanisms to maintain the polymorphism of DQAgenes in Tibetan sheep. The changes of DQA genes among groups in 5 ecological Tibetan sheep from Gansu and Qinghai were less than those among population with groups, suggesting that the DQA genes in Tibetan sheep generates positive selection and adaptive evolution. This research results will provide basic data for genetic improvement and germplasm innovation of Tibetan sheep.
引文
沈永义.2010.基因组学与动物适应性进化研究-中国青年遗传学家论坛论文摘要汇编[C].浙江嘉兴:2010中国青年遗传学家论坛,102.(Shen Y Y.2010.Research on the evolution of the genome and the animal adaptabilityChina Youth Forum of the geneticist assembly[C].ZheJiang Jiaxing:2010 Chinese young geneticist Forum,102.)
曾倩倩.2013.红腹锦鸡MHCⅠ类座位的分离及其适应性进化研究[D].博士学位论文,浙江大学,导师,方盛国.(Zeng Q Q.2013.Isolation of MHC classⅠloci and the adative evolutionary studies of MHC for the golden pheasant[D].Dissertation for ph.D.,Zhejiang University,Supervisor:Fang S G.)
Aguilar A,Roemer G,Debenham S,et al.2004.High MHC diversity maintained by balancing selection in an otherwise genetically monomorphic mammal[J].Proceedings of the National Academy of Science of the USA,101(10):3490-3494.
Babik W,Pabijan M,Radwan J.2008.Contrasting patterns of variation in MHC loci in the Alpine newt[J].Molecular Ecology,17(10):2339-2355.
Bowen L,Aldridge B M,Gulland F,et al.2002.Molecular characterization of expressed DQA and DQB genes in the California sea lion(Zalophus californianus)[J].Immunogenetics,54(5):332-347.
Dukkipati V S,Blair H T,Garrick D J,et al.2006.'OvarMhc'-ovine major histocompatibility complex:Structure and gene polymorphisms[J].Genetics and Molecular Research,5(4):581-608.
Excoffier L,Laval G,Schneider S,2005.Arlequin(version3.0):An integrated software package for population genetics data analysis[J].Evolutionary Bioinformatics,1:47-50.
Frantz A C,Pope L C,Etherington T R,et al.2010.Using isolation-by-distance-based approaches to assess the barrier effect of linear landscape elements on badger(Meles meles)dispersal[J].Molecular Ecology,19(8):1663-1674.
Furlong R F,Yang Z H.2008.Diversifying and purifying selection in the peptide binding region of DRB in mammals[J].Journal of Molecular Evolution,66(4):384-394.
Hickford J G,Zhou H,Slow S,et al.2004.Diversity of the ovine DQA2 gene[J].American Society of Animal Science,82:1553-1563.
Kikkawa E F,Tsuda T T,Sumiyama D,et al.2009.Trans-species polymorphism of the Mhc classⅡDRB-like gene in banded penguins(genus Spheniscus)[J].Immunogenetics,61(5):341-352.
Kita Y F,Hosomichi K,Kohara S,et al.2009.MHC classⅠAloci polymorphism and diversity in three Southeast Asian populations of cynomolgus macaque[J].Immunogenetics,61(9):635-648.
Nielsen R.2005.Molecular signatures of natural selection[J].Annual Review of Genetics,39:197-218.
Piertney S B,Oliver M K.2006.The evolutionary ecology of the major histocompatibility complex[J].Heredity(Edinb),96(1):7-21.
Sambrook J,Fritsch E F,Maniatis T.2001.Molecular Cloning:A Laboratory Manual[M].3rd ed.New York:Cold Spring Harbor Laboratory Press.
Seddon J M,Ellegren H.2004.A temporal analysis shows major histocompatibility complex loci in the Scandinavian wolf population are consistent with neutral evolution[J].Proceedings of the Royal Society B-Biological Sciences,271(1554):2283-2291.
Sommer S.2005.The importance of immune gene variability(MHC)in evolutionary ecology and conservation[J].Frontiers in Zoology,2:16-33.
Surridge A K,van der Loo W,Abrantes J,et al.2008.Diversity and evolutionary history of the MHC DQA gene in leporids[J].Immunogenetics,60(9):515-525.
Sutton J T,Nakagawa S,Robertson B C,et al.2011.Disentangling the roles of natural selection and genetic drift in shaping variation at MHC immunity genes[J].Molecular Ecology,20(21):4408-4420.
Takeshima S N,Sarai A,Saitou N,et al.2009.MHC classⅡDR classification based on antigen-binding groove natural selection[J].Biochemical and Biophysical Research Communication,385(2):967-978.
Tizard I R.2004.Acquired immunity:Antigen-presenting receptors.In:Veterinary immunology:An introduction[C].Philadelphia,USA,Elsevier,67-77.
Ujvari B,Belov K.2011.Major histocompatibility complex(MHC)markers in conservation biology[J].International Journal of Molecular Sciences,12(8):5168-5186.
Weber D S,Stewart B S,Schienman J,et al.2004.Major histocompatibility complex variation at three classⅡloci in the northern elephant seal[J].Molecular Ecology,13(3):711-718.
Westerdahl H,Waldenstrom J,Hansson B,et al.2005.Associations between malaria and MHC genes in a migratory songbird[J].Proceedings of the Royal Society B:Biological Sciences,272(1571):1511-1518.
Worley K,Gillingham M,Jensen P,et al.2008.Single locus typing of MHC classⅠand classⅡB loci in a population of red jungle fowl[J].Immunogenetics,60(5):233-247.
Zhou H,Hickford J G.2004.Allelic polymorphism in the ovine DQA1 gene[J].American Society of Animal Science,82:8-16.