title: Origin of Amniote Sex Chromosomes: An Ancestral Super-Sex Chromosome, or Common Requirements?
abstract: The diversity of sex chromosomes among amniotes is the product of independent evolution of different systems in different lineages, defined by novel sex-determining genes. Convergent evolution is very common, suggesting that some genes are particularly adept at taking on a sex-determining role. Comparative gene mapping, and more recently whole genome sequencing, have now turned up other surprising relationships; different regions of the amniote genome that have become sex determining in some taxa seem to share synteny, or share sequence, in others. Is this, after all, evidence that these regions were once linked in a super-sex chromosome that underwent multiple fission in different ways in different amniote lineages? Or does it signify that special properties of sex chromosomes (paucity of active genes, low recombination, epigenetic regulation to achieve dosage compensation) predispose particular chromosomes to a sex-determining role?
authors.affiliation: From the Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, Australia (Ezaz, Graves); Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan, Lat Yao, Chatuchak, Bangkok 10900, Thailand (Srikulnath); and School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (Graves). Tariq.Ezaz@canberra.edu.au.
authors.forename: Tariq
authors.initials: T
authors.lastname: Ezaz
authors.affiliation: From the Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, Australia (Ezaz, Graves); Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan, Lat Yao, Chatuchak, Bangkok 10900, Thailand (Srikulnath); and School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (Graves).
authors.forename: Kornsorn
authors.initials: K
authors.lastname: Srikulnath
authors.affiliation: From the Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, Australia (Ezaz, Graves); Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan, Lat Yao, Chatuchak, Bangkok 10900, Thailand (Srikulnath); and School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (Graves).
authors.forename: Jennifer A Marshall
authors.initials: JA
authors.lastname: Graves
mesh_terms: D000818:Animals; D004843:Epistasis, Genetic; D019143:Evolution, Molecular; D012730:Sex Chromosomes; D019849:Sex Determination Processes; D026801:Synteny
keywords: comparative gene mapping; sex chromosome evolution; sex determination