title: Which came first,  the feather or the bird?
authors.forename: O Richard
authors.initials: OR
authors.lastname: Prum
authors.forename: Alan H
authors.initials: AH
authors.lastname: Brush
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation; D025061:Dinosaurs; D005241:Feathers / Q000166:cytology / Q000254:growth & development; D005580:Fossils; D053823:Hedgehog Proteins; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D016212:Transforming Growth Factor beta
chemical_list: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D053823:Hedgehog Proteins; D015534:Trans-Activators; D016212:Transforming Growth Factor beta