|Smith, Timothy - Tim|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2007
Publication Date: 11/2/2007
Publication URL: http://jas.fass.org/cgi/reprint/85/11/2807
Citation: Casas, E., White, S.N., Shackelford, S.D., Wheeler, T.L., Koohmaraie, M., Bennett, G.L., Smith, T.P.L. 2007. Assessing the association of single nucleotide polymorphisms at the thyroglobulin gene with carcass traits in beef cattle. Journal of Animal Science. 85:2807-2814. Interpretive Summary: A commercially available DNA marker associated with differences in marbling score in beef cattle can be used to improve beef quality. It was unknown if its effect could be consistently ascertained in widely varying breeds of cattle in the United States. The marker was tested in three diverse populations of cattle. These populations comprised breeds of cattle used in beef production, dairy breeds used in beef production, and tropically adapted Bos taurus breeds. The DNA marker was associated with marbling score in cattle with inheritance from Japanese Black cattle (Wagyu). The marker may explain a portion of the variation observed for marbling score in beef cattle; however, further studies will be needed to establish the effect of this DNA marker with marbling score.
Technical Abstract: The objective of this study was to assess the association of single nucleotide polymorphisms in the thyroglobulin gene, including a previously reported marker in current industry use, with marbling score in beef cattle. Three populations, designated GPE6, GPE7, and GPE8, were studied. The GPE6 population sampled breeds that could be used as alternative germplasm sources in beef cattle production including Wagyu, Swedish Red and White, Friesian, and Norwegian Red. The GPE7 population sampled seven popular beef cattle breeds used in temperate climates of the United States: Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental. The GPE8 population sampled Bos indicus-influenced breeds used in subtropical regions of the country and subtropical and tropical regions of the world, including Beefmaster, Bonsmara, Brangus, and Romosinuano. Evaluation of six single nucleotide polymorphisms in the thyroglobulin gene, including five newly described variations, showed no association (P > 0.10) with marbling score in these populations except a tendency (P < 0.10) for association with the previously described marker in GPE6. Closer examination of the GPE6 data revealed the source of the tendency was an association (P < 0.02) with marbling in animals of Wagyu inheritance. Animals having a Wagyu background and inheriting the TT genotype had higher marbling score (599 +/ 20) than those inheriting the CC (540 +/ 10) or the CT (541 +/ 11) genotype. No association was detected with any other carcass trait for this marker in the three populations. Furthermore, none of the five newly described markers in the gene displayed an association with marbling score. The data indicate that markers at the thyroglobulin gene may be a useful predictor of marbling performance for producers utilizing Wagyu-based cattle. Although associations with marbling score in the remaining populations were not large or significant, the TT genotype had the highest marbling score in each population.