The major histocompatibility complex of the turkey.

Abstract

The ability to identify between self and foreign pathogens is a key function of the vertebrate immune system. To achieve this, vertebrates have developed complex genetic and epigenetic mechanisms to provide sufficient variability to respond to continuously evolving pathogens or transformed cells they face. One of these systems is the large and highly polymorphic major histocompatibility complex (MHC), responsible for the presentation of endogenous and exogenous peptide antigens to T cells. The degree of polymorphism, number of gene copies, and the co-dominant expression of genes of the mammalian MHC allows for a great number possible antigens to be presented. Compared to mammals, the chicken MHC (MHC-B) is greatly condensed, containing the major histocompatibility antigens in a region of just 50 kb with a reduction in gene copy numbers and a lack of co-dominant expression. In addition to the MHC-B, the chicken has a second MHC-like region (MHC-Y) located on the same microchromosome as B yet it is genetically unlinked. The work presented in this dissertation physically and genetically maps the homologous MHC regions in the turkey and identifies genes within these regions. Further work surveyed the polymorphism content within commercial and wild turkeys. A final study assayed the genome-wide diversity of the individual from which the MHC was sequenced to determine the appropriateness of this source DNA for whole genome sequencing. These data provide helpful background information to advance turkey whole genome sequencing and develops genomic resources for the study of the effect of MHC alleles on the outcome of pathogenic infections in the turkey