Differential expression of FOXO1 during development and myoblast differentiation of Qinchuan cattle and its association analysis with growth traits.

Our previous work reported a relationship between FOXO1 mutations and growth of Qinchuan (QC) cattle. Here, we performed differential expression analysis of FOXO1 and its association analysis with growth traits in QC cattle. First, we measured the expression of the FOXO1 gene in nine tissues during three developmental stages. The results showed that FOXO1 was abundantly expressed in tissues of calves but was strongly repressed in adulthood, although there was significant transcription in skeletal muscle. FOXO1 expression showed gradual up-regulation during differentiation of primary bovine skeletal muscle cells. We also identified six SNPs of the bovine FOXO1 gene by sequencing DNA pools of samples from 488 individuals, and association analysis indicated that five SNPs were significantly associated with some growth traits in the QC population. We further analyzed four haplotype combinations of the six SNPs and found significant correlation with body length (P<0.01). In conclusion, FOXO1 participates in bovine myocyte differentiation and expression, and may be a strong candidate as a gene that affects growth traits that could be exploited in a QC cattle breeding program. More generally, our data provide a new theoretical basis for QC beef breeding and beef quality improvement.