Date of Award
Doctor of Philosophy
Max F. Rothschild
Recently, numerous genes and genomic regions associated with pork quality were identified. There is great potential for the pig industry in using information from molecular markers for the improvement of pork quality traits, such as color, marbling and pH. Besides the traditional fresh pork market, the production of dry-cured pork products, like Country Hams, has also increased. We collected data on fresh and dry-cured Country Hams to investigate the relationships between these traits and to analyze the effect of genetic markers on fresh and dry-cured ham processing characteristics. Significant positive correlations between yield and firmness, color, pH and marbling were detected, indicating that good pork quality is necessary to maximize Country Ham yield. Additionally, a number of genetic markers was significantly associated with yield and fresh pork quality, including the cathepsin F and stearoyl-CoA desaturase genes. Other chromosomal regions affecting pork quality were identified in genome scans, an approach that identified numerous QTL (quantitative trait loci) for pork quality. However, the mutations underlying these QTL need to be identified first in order for the industry to take full advantage of this information. We mapped 21 genetic markers to a QTL region for meat color and lactate related traits located on pig chromosome 17 (SSC17). As a consequence, the marker density of the SSC17 QTL region was greatly improved. This is an important and necessary first step towards the identification of QTL causative mutations. We then dissected the QTL region on SSC17 using a combination of approaches that included novel QTL mapping approaches and the assembly of the largest continuous contig of pig sequence to date. After the regions more likely to contain the QTL causative mutations were identified we individually sequenced 14 genes in these regions and several polymorphisms were discovered, including non-synonymous exonic polymorphisms. Further analyses of the data identified mutations in two genes, AURKA (aurora kinase A) and BMP7 (bone morphogenetic protein 7), that can potentially be responsible for the observed QTL, as well as other markers in linkage disequilibrium with the QTL traits. These results will be helpful for possible pig selection schemes using molecular genetics information.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Antonio Marcos Costa do Amaral Ramos
Costa do Amaral Ramos, Antonio Marcos, "Molecular dissection of genomic regions influencing important economic traits in the pig " (2006). Retrospective Theses and Dissertations. 1926.