MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus)

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dc.contributor.advisorBishop, Jacqueline Men_ZA
dc.contributor.advisorAmar, Arjunen_ZA
dc.contributor.authorLe Roux, Liezlen_ZA
dc.date.accessioned2015-12-09T14:41:31Z
dc.date.available2015-12-09T14:41:31Z
dc.date.issued2015en_ZA
dc.description.abstractThe major histocompatibility complex (MHC) is a multigene family known to be the most variable gene group in vertebrates in terms of allelic diversity and gene number. Pathogen mediated selection is thought to be the major driving force behind the unusually high levels of MHC polymorphism in natural populations. In this study the relationship between MHC class I diversity and blood parasite infection intensity is explored in a population of black sparrowhawks (Accipiter melanoleucus). The species is of particular ecological and evolutionary interest as black sparrowhawks display a discrete polymorphism in plumage pattern across its range, occurring as a light and dark morph. It is well established in birds that carotenoïd and melanin-based pigmentation patterns are often associated with parasite resistance. In this study, functional variation at the peptide binding region (PBR) of MHC class I loci is investigated to explain individual variation in blood parasite infection in black sparrowhawks. Using DNA sequence data together with individual estimates of blood parasite load (for Haemoproteus nisi and Leucocytozoon toddi); the study tested the relationship between (i) allelic diversity and individual parasite load and (ii) specific alleles and individual parasite load using a Generalized Linear Model framework. Seven different, putatively functional, MHC class I alleles were identified. Number of alleles per individual ranged from one to three in individuals infected with H. nisi, whereas individuals infected with L. toddi had either two or three different alleles. A significant positive association was found between H. nisi infection intensity and MHC allele Acme_BF2*03. No significant association was found between L. toddi infection intensity and a specific allele. The results reported support the role of pathogen mediated selection of genetic variation at evolutionary relevant MHC genes through rare allele advantage. By characterizing the variation at MHC class I loci and testing for a relationship with parasitemia, it is now possible to elucidate the mechanisms and significance of MHC molecular adaptation in the black sparrowhawk.en_ZA
dc.identifier.apacitationLe Roux, L. (2015). <i>MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus)</i>. (Thesis). University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology. Retrieved from http://hdl.handle.net/11427/15722en_ZA
dc.identifier.chicagocitationLe Roux, Liezl. <i>"MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus)."</i> Thesis., University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2015. http://hdl.handle.net/11427/15722en_ZA
dc.identifier.citationLe Roux, L. 2015. MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus). University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Le Roux, Liezl AB - The major histocompatibility complex (MHC) is a multigene family known to be the most variable gene group in vertebrates in terms of allelic diversity and gene number. Pathogen mediated selection is thought to be the major driving force behind the unusually high levels of MHC polymorphism in natural populations. In this study the relationship between MHC class I diversity and blood parasite infection intensity is explored in a population of black sparrowhawks (Accipiter melanoleucus). The species is of particular ecological and evolutionary interest as black sparrowhawks display a discrete polymorphism in plumage pattern across its range, occurring as a light and dark morph. It is well established in birds that carotenoïd and melanin-based pigmentation patterns are often associated with parasite resistance. In this study, functional variation at the peptide binding region (PBR) of MHC class I loci is investigated to explain individual variation in blood parasite infection in black sparrowhawks. Using DNA sequence data together with individual estimates of blood parasite load (for Haemoproteus nisi and Leucocytozoon toddi); the study tested the relationship between (i) allelic diversity and individual parasite load and (ii) specific alleles and individual parasite load using a Generalized Linear Model framework. Seven different, putatively functional, MHC class I alleles were identified. Number of alleles per individual ranged from one to three in individuals infected with H. nisi, whereas individuals infected with L. toddi had either two or three different alleles. A significant positive association was found between H. nisi infection intensity and MHC allele Acme_BF2*03. No significant association was found between L. toddi infection intensity and a specific allele. The results reported support the role of pathogen mediated selection of genetic variation at evolutionary relevant MHC genes through rare allele advantage. By characterizing the variation at MHC class I loci and testing for a relationship with parasitemia, it is now possible to elucidate the mechanisms and significance of MHC molecular adaptation in the black sparrowhawk. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus) TI - MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus) UR - http://hdl.handle.net/11427/15722 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15722
dc.identifier.vancouvercitationLe Roux L. MHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus). [Thesis]. University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/15722en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherConservation Biologyen_ZA
dc.titleMHC Class I diversity influences haematozoon infection intensity in the polymorphic black sparrowhawk (Accipiter melanoleucus)en_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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