The Integument of Vertebrates and the Specification of the Corneal Epithelium

The study explored the development of the integument, specifically the corneal epithelium, in vertebrates, focusing on its embryonic origins and differentiation. It was found that the corneal epithelium differentiation is independent of its mesenchyme, and the corneal program is established as a default when lens formation is inhibited. Experiments on chick embryos demonstrated that inhibiting BMP signaling, necessary for lens differentiation, resulted in eyes without a lens but with a K12 positive corneal epithelium. This indicated that both the lens and cornea originate from common precursor cells, and the corneal program is the overriding default when lens development is disrupted. The study identified 3,621 genes co-expressed in corneal epithelium and hair follicle stem cells, with 1,768 genes unique to the cornea, including Pax6 and K12, highlighting the molecular profile of corneal differentiation.