title: Evidence for a single loss of mineralized teeth in the common avian ancestor.
abstract: Edentulism, the absence of teeth, has evolved convergently among vertebrates, including birds, turtles, and several lineages of mammals. Instead of teeth, modern birds (Neornithes) use a horny beak (rhamphotheca) and a muscular gizzard to acquire and process food. We performed comparative genomic analyses representing lineages of nearly all extant bird orders and recovered shared, inactivating mutations within genes expressed in both the enamel and dentin of teeth of other vertebrate species, indicating that the common ancestor of modern birds lacked mineralized teeth. We estimate that tooth loss, or at least the loss of enamel caps that provide the outer layer of mineralized teeth, occurred about 116 million years ago.
authors.affiliation: Department of Biology and Molecular Biology, Montclair State University, Montclair, NJ 07043, USA. meredithr@mail.montclair.edu mark.springer@ucr.edu.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Meredith
authors.affiliation: China National GeneBank, Beijing Genomics Institute-Shenzhen, Shenzhen, 518083, China. Centre for Social Evolution, Department of Biology, Universitetsparken 15, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors.forename: Guojie
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen Øster Voldgade 5-7, 1350 Copenhagen, Denmark. Trace and Environmental DNA Laboratory, Department of Environment and Agriculture, Curtin University, Perth, Western Australia 6102, Australia.
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
authors.affiliation: Department of Neurobiology, Howard Hughes Medical Institute and Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Erich D
authors.initials: ED
authors.lastname: Jarvis
authors.affiliation: Department of Biology, University of California, Riverside, CA 92521, USA. meredithr@mail.montclair.edu mark.springer@ucr.edu.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Springer
mesh_terms: D000489:Alligators and Crocodiles / Q000235:genetics; D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics*; D003743:Dental Enamel; D003804:Dentin; D019143:Evolution, Molecular; D005580:Fossils; D016678:Genome; D023281:Genomics; D008322:Mammals / Q000235:genetics; D009154:Mutation; D010802:Phylogeny; D014070:Tooth; D014714:Vertebrates / Q000235:genetics*