title: Sex reversal triggers the rapid transition from genetic to temperature-dependent sex.
abstract: Sex determination in animals is amazingly plastic. Vertebrates display contrasting strategies ranging from complete genetic control of sex (genotypic sex determination) to environmentally determined sex (for example, temperature-dependent sex determination). Phylogenetic analyses suggest frequent evolutionary transitions between genotypic and temperature-dependent sex determination in environmentally sensitive lineages, including reptiles. These transitions are thought to involve a genotypic system becoming sensitive to temperature, with sex determined by gene-environment interactions. Most mechanistic models of transitions invoke a role for sex reversal. Sex reversal has not yet been demonstrated in nature for any amniote, although it occurs in fish and rarely in amphibians. Here we make the first report of reptile sex reversal in the wild, in the Australian bearded dragon (Pogona vitticeps), and use sex-reversed animals to experimentally induce a rapid transition from genotypic to temperature-dependent sex determination. Controlled mating of normal males to sex-reversed females produces viable and fertile offspring whose phenotypic sex is determined solely by temperature (temperature-dependent sex determination). The W sex chromosome is eliminated from this lineage in the first generation. The instantaneous creation of a lineage of ZZ temperature-sensitive animals reveals a novel, climate-induced pathway for the rapid transition between genetic and temperature-dependent sex determination, and adds to concern about adaptation to rapid global climate change.
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Holleley
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: 1] Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia [2] School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Marshall Graves
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Tariq
authors.initials: T
authors.lastname: Ezaz
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Matsubara
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Bhumika
authors.initials: B
authors.lastname: Azad
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Xiuwen
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Arthur
authors.initials: A
authors.lastname: Georges
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001315:Australia; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D012104:Reptiles; D012730:Sex Chromosomes / Q000235:genetics; D019849:Sex Determination Processes / Q000235:genetics / Q000502:physiology*; D012744:Sex Ratio; D013696:Temperature