Vrtn, or vertnin, is a gene with significant roles in mammalian development. It is a novel DNA-binding transcription factor that localizes in the nucleus, binds to DNA across the genome, and regulates the transcription of genes containing its binding motifs. Vrtn is essential for the development of thoracic vertebrae and is involved in somitogenesis. It also modulates somite segmentation via the Notch signaling pathway [1].

In Vrtn-null embryos, there are somitogenesis defects, including failure of axial rotation and fewer somites at the thoracic somite stage. Half of Vrtn heterozygous mice show abnormal spinal development with fewer thoracic vertebrae and ribs compared to wild-type littermates. These findings from mouse models reveal the crucial role of Vrtn in thoracic vertebrae development [1].

In conclusion, Vrtn is essential for the development of thoracic vertebrae in mammals. The gene knockout and heterozygous mouse models have provided valuable insights into its function in vertebral development. Understanding Vrtn can potentially contribute to improving pork production by selecting alleles that increase the number of thoracic vertebrae and ribs, as well as having implications for understanding the genetic basis of vertebral number in other animals like sheep [1,2,3].