Effect of thyroglobulin gene polymorphisms on growth, carcass composition and meat quality traits in Chinese beef cattle.

The thyroglobulin (TG) gene has been studied as an important gene related to fat deposition, since not only does TG gene locate in a quantitative trait locus with an effect on fat deposition, but also it encodes the precursor of thyroid hormones which have crucial biological functions in energy metabolism. In the present study, we identified four novel SNPs at the 5' flanking region of the bovine TG gene. Association analysis indicated that the G275A, G277C, G280A and C281G SNPs were significantly associated with average daily gain (ADG, P < 0.01 for G275A and G277C, P < 0.05 for G280A and C281G). Five haplotypes for the 4 SNPs were constructed and their effects on growth, carcass composition and meat quality traits were evaluated. The results showed no significant effect of haplotype on ADG. Meanwhile, no significant association was found between 4 SNPs and other growth, carcass composition and meat quality traits including intramuscular fat. Bioinformatics analysis showed that 4 SNPs may results in potential transcription factor binding site changes. Results of this study suggest that TG gene-specific SNPs may be a useful marker for growth traits in marker assisted selection programs in beef cattle.