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Title: Genetic resistance to nematode infection in Texel
Author: Md Isa, Nur Mahiza
ISNI:       0000 0004 5916 7307
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 2016
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Nematode infection is one of the major causes of disease in young sheep. Selective breeding of genetically nematode resistant sheep is an alternative method for controlling the nematode infection. This process could be simplified if loci that account for nematode resistance can be identified. MHC is one of the candidates and several studies have confirmed the association between MHC alleles and nematode resistance. The aim of this study is to establish the role of MHC class II genes in nematode resistance in Texel sheep. Thus, it can help endorse the usefulness of the MHC class II genes as a genetic marker of nematode resistance and extend the knowledge of the mechanism of resistance against nematodes. This study has been focused on three main areas; 1) description of MHC class II gene diversity, 2) description of haplotype and linkage disequilibrium pattern at MHC class II genes and 3) the association of MHC class II genes and nematode resistance. Sequence-based typing was applied to characterise MHC class II allelic diversity in 235 Texel lambs. The haplotype and linkage disequilibrium patterns were deduced from pedigree information. Finally, the association between MHC class II haplotypes and nematode resistance (FEC and IgE activity against L3) were investigated using a MIXED model approach. MHC class IIa genes were diverse in Texel, consistent with previous studies reported in sheep. The most polymorphic locus among MHC class IIa genes was DRB1. A total of 21 distinct DR-DQ haplotypes were obtained and strong linkage disequilibrium exhibited between DR-DQ genes. There were also statistically significant associations of specific haplotypes and nematode resistance in this population. The work in this thesis confirms the likely importance of MHC genes in regulating resistance against gastrointestinal nematodes, thus supporting the use of MHC as a genetic marker of nematode resistance in selective breeding. Sequence-based typing system for MHC class IIa has been established in this study.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Q Science (General) ; QR180 Immunology ; S Agriculture (General)