title: Molecular evolution of Dmrt1 accompanies change of sex-determining mechanisms in reptilia.
abstract: In reptiles, sex-determining mechanisms have evolved repeatedly and reversibly between genotypic and temperature-dependent sex determination. The gene Dmrt1 directs male determination in chicken (and presumably other birds), and regulates sex differentiation in animals as distantly related as fruit flies, nematodes and humans. Here, we show a consistent molecular difference in Dmrt1 between reptiles with genotypic and temperature-dependent sex determination. Among 34 non-avian reptiles, a convergently evolved pair of amino acids encoded by sequence within exon 2 near the DM-binding domain of Dmrt1 distinguishes species with either type of sex determination. We suggest that this amino acid shift accompanied the evolution of genotypic sex determination from an ancestral condition of temperature-dependent sex determination at least three times among reptiles, as evident in turtles, birds and squamates. This novel hypothesis describes the evolution of sex-determining mechanisms as turnover events accompanied by one or two small mutations.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA janesdaniele@gmail.com.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Janes
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Organ
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Rami
authors.initials: R
authors.lastname: Stiglec
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Denis
authors.initials: D
authors.lastname: O'Meally
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Sarre
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Arthur
authors.initials: A
authors.lastname: Georges
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Jennifer A M
authors.initials: JA
authors.lastname: Graves
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Valenzuela
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Literman
authors.affiliation: Allen Wilson Centre, Department of Anatomy, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Kim
authors.initials: K
authors.lastname: Rutherford
authors.affiliation: Allen Wilson Centre, Department of Anatomy, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Neil
authors.initials: N
authors.lastname: Gemmell
authors.affiliation: Department of Biology, Earlham College, Richmond, IN 47374, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Iverson
authors.affiliation: Department of Biology, University of Northern Iowa, Cedar Falls, IA 50614, USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Tamplin
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Scott V
authors.initials: SV
authors.lastname: Edwards
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Tariq
authors.initials: T
authors.lastname: Ezaz
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D005260:Female; D008297:Male; D012104:Reptiles / Q000502:physiology*; D019849:Sex Determination Processes; D014157:Transcription Factors / Q000235:genetics*
chemical_list: C110547:DMRT1 protein; D014157:Transcription Factors
keywords: ancestral reconstruction; archosaur; convergence; sex determination; squamate