FAS and Blindness: The other genes with multiple evidence of positive selection were Fas (TNFRSF6) binding factor 1 (FBFB1), which binds to keratin and plays a role in epithelial cell polarization [53]; the gene encoding Usher syndrome 1C binding protein 1 (USHBP1), which binds to the protein responsible for Usher syndrome type 1C, a sensory defect involving deafness and blindness [54]; and two genes from the Enhancer of split Groucho family, TLE4 and TLE6, which are involved in cell fate decision and boundary formation [55].