We are using novel genetic, molecular and cytological approaches to build a picture of the mechanisms of sex determination in the central bearded dragon, Pogona vitticeps and other squamates. Central questions we address are: Which chromosomes are the sex chromosomes and what genes do they contain among which is the master switch? How does temperature exert its influence in species with thermolabile sex? What drives transitions in the relative influence of genotype and environment, and how do gene-environment interactions play out in the wild?


Alam, S.M.I., Altmanová, M., Prasongmaneerut, T., Georges, A., Sarre, S.D., Nielsen, S.V., Gamble,T., Srikulnath, K., Rovatsos, M., Kratochvíl, L. and Ezaz, T. 2020. Cross-species BAC mapping highlights conservation of chromosome synteny across dragon lizards (Squamata: Agamidae) Genes 11, 698. [pdf]

Alam, S.M.I., Sarre, S.D., Georges, A. and Ezaz, T. 2020. Karyotype characterisation of two Australian dragon lizards (Squamata: Agamidae: Amphibolurinae) reveals subtle chromosomal rearrangements between related species with similar karyotypes, Cytogenetic and Genome Research, in press [accepted 2-Sep-2020].

Capraro, A., O‘Meally, D., Waters, S.A, Patel, H.R., Georges, A., and Waters, P.D. 2020. The role of microRNAs in regulating neuroprotection in the brain of hibernating central bearded dragons. Scientific Reports, in press [accepted 18-Mar-20]

Castelli, M., Georges, A. and Holleley, C.E. 2020. Corticosterone does not have a role in temperature sex reversal in the central bearded dragon (Pogona vitticeps). Submitted.

Castelli, M., Georges, A., Cherryh, C., Rosauer, D., Sarre, S.D., Contador-Kelsall, I. and Holleley, C.E. 2020. Evolving thermal thresholds may explain the distribution of temperature sex reversal in an Australian dragon lizard (Pogona vitticeps). Diversity and Distributions, in review.

Castelli, M., Whiteley, S., Georges, A. and Holleley, C.E. 2020. Cellular calcium and redox regulation: The mediator of vertebrate environmental sex determination? Biological Reviews 95:680-695. [pdf]

Cornejo-Páramo, P., Martínez-Pacheco, M.L., Lira-Noriega, A., Dissanayake, D.S.B., Acosta, A., Ramírez-Suástegui, C., Méndez-de-la-Cruz, F.R., Székely, T., Urrutia, A.O., Georges, A., Cortez, D. 2020. Viviparous reptile regarded to have temperature-dependent sex determination has old XY chromosomes. Genome Biology and Evolution 12:924–930. [pdf]

Dissanayake, D., Holleley, C.E., Deakin, J. and Georges, A. 2020. High altitude increases the risk of Y chromosome loss in Alpine skink populations with sex reversal. [in review]

Dissanayake, D.S.B., Holleley, C.E., Hill, L., O'Meally, D., Deakin, J. and Georges, A. 2020. Identification of Y chromosome markers in the eastern three-lined skink (Bassiana duperreyi) using in-silico whole genome subtraction. BMC Genomics, in press [accepted 8-Jul-20]

Jones, M.E.H., Pistevos, J.C.A., Cooper, N.H., Lappin, A.K., Georges, A., Hutchinson, M.N. and Holleley, C.E. 2020. Reproductive phenotype predicts adult bite-force performance in sex-reversed dragons. Journal of Experimental Zoology A 333:252-263. [pdf]

Rovatsos, M., Gamble, A., Nielsen, S., Georges, A., Ezaz, T. and Kratochvil, L. 2020. Do male and female heterogamety really differ in expression regulation? Lack of global dosage balance in pygopodid geckos. Philosophical Transactions of the Royal Society, Series B, in Press [accepted 20-May-2020]. https://www.biorxiv.org/content/10.1101/2020.06.03.132241v1

Schwanz, L.E., Georges, A., Holleley, C.E. and Sarre, S.D. 2020. Climate change, sex reversal and lability of sex determining mechanisms Journal of Evolutionary Biology 33:270-281. [pdf]

Whiteley, S., Georges, A., Weisbecker, V., Schwanz, L.E., and Holleley, C.E. 2020. Ovotestes suggest cryptic genetic influence in a reptile model for temperature dependent sex determination. [in review]

Whiteley, S.L., Holleley, C.E., Blackburn, J., Deveson, I.W., Wagner, S., Graves, J.A.M., Georges, A. 2020. Two transcriptionally distinct pathways drive female development in a reptile with genetic sex determination and temperature induced sex reversal. [in review].

Capraro, A., O'Meally, D., Georges, A. and Waters, P. 2019. The role of miRNAs in the hibernation of the central bearded dragon. SMBE 2019, Manchester Central, England. 21-25 July, 2019.

Capraro, A., O'Meally, D., Waters, S.A., Patel, H.R., Georges, A. and Waters, P.D. 2019. Waking the sleeping dragon: transcriptional profiling of a hibernating reptile. BMC Genomics 20:460. [pdf]

Matsubara, K., O’Meally, D., Sarre, S.D., Georges, A., Matsuda, Y., Graves, J.A.M., Srikulnath, K., Ezaz, T. 2019. ZW sex chromosomes in Australian dragon lizards (Agamidae) originated from a combination of duplication and translocation in the nucleolar organizing region. Genes 10:861 [pdf]

Alam, S., Sarre, S.D., Gleeson, D., Georges, A. and Ezaz, T.E. 2018. Methylation-sensitive DArTSeq derived SNPs for comparative genome analysis. Annual Conference of the Genetics Society of Australasia, University of Canberra, July 1-4, 2018

Alam, S.M.I, Sarre, S.D., Gleeson, D., Georges,A. and Ezaz, T. 2018. Did Lizards Follow Unique Pathways in Sex Chromosome Evolution? Genes 2018 9(5):239

Alam, S.M.L., Georges, A., Gleeson, D., Sarre, S.D. and Ezaz, T. 2018. Sex-linked markers in the Australian grassland earless dragon Tympanocryptis pinguicolla. Combined Meeting of the Australian Society of Herpetologists and the Society for Research on Amphibians and Reptiles in New Zealand. November 15-18, 2018. Kindilan, Queensland

Capraro, A., Georges, A. and Waters, P. 2018. Waking the sleeping dragon: epigenetic mechanisms that govern hibernation in the central bearded dragon. Annual Conference of the Genetics Society of Australasia, University of Canberra, July 1-4, 2018

Castelli, M., Cherryh, C., Georges, A. and Holleley, C.E. 2018. Sex reversal is a geographically and temporally widespread phenomenon in the central bearded dragon. Annual Conference of the Genetics Society of Australasia, University of Canberra, July 1-4, 2018

Dissanayake, D., Hill., L, Holleley, C., Deakin, J., and Georges, A. 2018. How sex can go wrong in the cold: Sex reversal of wild alpine skinks Bassiana duperreyi (Eastern Three-lines Skink). Combined Meeting of the Australian Society of Herpetologists and the Society for Research on Amphibians and Reptiles in New Zealand. November 15-18, 2018. Kindilan, Queensland.

Georges, A. and Holleley, C.E. 2018. How does temperature determine sex? Temperature-responsive epigenetic regulation clarifies a 50-year-old mystery in reptiles. Science 360:601-602 [pdf]

Georges, A. and Patel, H. 2018. Using gene synteny to define putative superscaffolds as an aid to physical mapping. Annual Conference of the Genetics Society of Australasia, University of Canberra, July 1-4, 2018

Georges, A., Spencer, R.J., Kilian, A., Welsh, M. and Zhang, X. 2018. Assault from all sides: Hybridization and introgression threaten the already critically endangered Myuchelys georgesi. Combined Meeting of the Australian Society of Herpetologists and the Society for Research on Amphibians and Reptiles in New Zealand. November 15-18, 2018. Kindilan, Queensland

Johnson, R.N., O’Meally, D., Chen, Z., Etherington, G.J., Ho, S.Y.W., Nash, W.J., Grueber, C.E., Cheng, Y., Whittington, C.M., Dennison, S., Peel, E., Haerty, W., O’Neill, R.J., Colgan, D, Russell, T.L., Alquezar-Planas, D.E., Attenbrow, V., Bragg, J.G., Brandies, P.A., Chong, A.Y-Y., Deakin, J.E., di Palma, F., Duda, Z., Eldridge, M.D.B., Ewart, K.M., Hogg, C.J., Frankham, G.J., Georges, A., Gillett, A.K., Govendir, M., Greenwood, A.D., Hayakawa, T., Helgen, K.M, Hobbs, M., Holleley, C.E., Heider, T.N., Jones, E.A., King, A., Madden, D., Graves, J.A.M., Morris, K.M., Neaves, L.E., Patel, H.R., Polkinghorne, A.P., Renfree, M.B.R., Robin, C., Salinas, R., Tsangaras, K., Waters, P.D., Waters, S.A., Wright, B., Wilkins, M.R., Timms, P. and Belov, K. 2018. Adaptation and conservation insights from the koala genome. Nature Genetics 50:1102–1111. [pdf]

Warner, D., Du, W. and Georges, A. 2018. Developmental plasticity in reptiles: Physiological mechanisms and ecological consequences. Journal of Experimental Zoology 329:153-161 [pdf]

Whiteley, S., Weisbecker, V., Georges, A., Gauthier, A.R.G., Whitehead, D.L. and Holleley, C.E. 2018. Developmental asynchrony and antagonism of sex determination pathways in a lizard with temperature-induced sex reversal. Scientific Reports 8:14892 [pdf]

Deveson, I.W., Holleley, C.E., Blackburn, J., Graves, J.A.M., Mattick, J.S., Waters, P.D. and Georges, A. 2017. Differential intron retention in Jumonji chromatin modifier genes is implicated in reptile temperature-dependent sex determination Science Advances 3:e1700731. [pdf]

Georges, A. 2017. The dragon genome -- sequence, annotation, physical mapping -- what we have learned an what questions have been raised. Cytogenetics in the Genomics Era. February 2-3, 2017, Canberra, Australia

Georges, A. 2017. Genetics, conservation and climate change: Lessons from the dragon. Genomics and Animal Conservation Symposium in Honour of Prof. Jennifer Graves and her receipt of the PM Prize for Science. LaTrobe University, Melbourne. September 29, 2017.

Georges, A. 2017. "Phenotypic plasticity in sex determination in reptiles" and "Sex in Dragons -- probing the mechanisms of sex determination" Amphibian Research Center, Hiroshima University, Japan. 27-July-2017. [Invited Presentation]

Whiteley, S. 2017. Sex reversal and temporary pseudohermaphroditism: Complex sexual development in the Central Bearded Dragon (Squamata: <i>Pogona vitticeps</i>) Honours Thesis, University of Queensland, Brisbane, Australia [pdf]

Whiteley, S.L., Holleley, C.E., Ruscoe, W., Castelli, M., Whitehead, D., Lei, J., Georges, A. and Weisbecker, V. 2017. Sex determination mode does not affect body or genital development of the central bearded dragon (Pogona vitticeps). EvoDevo 8:25. [pdf]

Deakin, J., Edwards, M.J., Patel, H., O'Meally, D., Lian, J., Stenhouse, R., Ryan, S., Livernois, A., Azad, B., Holleley, C., Li, Q. and Georges, A. 2016. Anchoring genome sequence to chromosomes of the central bearded dragon (Pogona vitticeps) enables reconstruction of ancestral squamate macrochromosomes and identifies sequence content of the Z chromosome. BMC Genomics 17:447. [pdf]

Ezaz, T., Matsubara, K., Gamble, T., O’Meally, D., Melanie Edwards, M., Young, M., Holleley, C., Matsuda, Y., Deakin, J., Zhang, X., Graves, J.A.M., Sarre, S.D. and Georges, A. 2016. Comparative genomics of sex chromosome evolution in Reptiles: Shared ancestry or convergence? The 8th World Congress of Herpetology, 15-21 August, 2016. Hangzhou, China.

Georges, A. 2016. Gene-environment interactions in reptile sex determination. Yellow Seas Fisheries Institute, Qingdao, China. 22-August-2016. [Invited Presentation]

Georges, A. 2016. Sex in dragons -- probing the interaction between genotype and environment. Institute of Zoology, Chinese Academy of Sciences, Beijing. 25-August-2016. [Invited Presentation]

Georges, A., Holleley, C. and Sarre, S.D. 2016. Developmental plasticity and sex determination in reptiles. The 8th World Congress of Herpetology, 15-21 August, 2016. Hangzou, China [Invited Presentation]

Georges, A., Holleley, H., O’Meally, D., Zhang,G., Lee, K., Waters, P., Deakin, D., Patel, H., Matsubara, K., Zhang, X.,Graves, J.A.M., Ezaz T. and Sarre, S.D.. 2016. Genome of the dragon and the genomics of sex. The 8th World Congress of Herpetology, 15-21 August, 2016. Hangzou, China [Invited Presentation]

Holleley, CE, Sarre, SD, O'Meally, D. and Georges, A. 2016. Sex reversal in reptiles: reproductive oddity or powerful driver of evolutionary change? Sexual Development doi:10.1159/000450972. [pdf]

Li, H., Holleley, C.E., Elphick, M., Georges, A. and Shine, R. 2016. The behavioural consequences of sex reversal in dragons. Proceedings of the Royal Society London, Series B 283: 20160217. [pdf]

Livernois, A., Hardy, K. Domaschenz, R, Papankilaou, A, Georges, A., Sarre, S., Rao, S., Ezaz, T. and Deakin, J. 2016. Identification of interleukin genes in Pogona vitticeps using a de novo transcriptome assembly from RNA-Seq data Immunogenetics 68:719–731. [pdf]

Matsubara, K., O'Meally, D., Azad, B., Georges, A., Sarre, S.D., Graves, J.A.M., Matsuda, Y. and Ezaz, T. 2016. Amplification of microsatellite repeat motifs is associated with the evolutionary differentiation and heterochromatinization of sex chromosomes in Sauropsida. Chromosoma 125:111-123. [pdf]

Georges, A., Li, Q., Lian, J., O'Meally, D., Deakin, J., Wang, Z., Zhang, P., Fujita, M., Patel, H.R., Holleley, C.E., Zhou, Y., Zhang, X., Matsurbara, K., Waters, P., Graves, J.A.M., Sarre, S.D. and Zhang, G. 2015. High-coverage sequencing and annotated assembly of the genome of the Australian dragon lizard Pogona vitticeps. GigaScience 4:45 [pdf]

Holleley, C.E., O'Meally, D., Sarre, S.D., Graves, J.A.M., Ezaz, T., Matsubara, K., Azad, B., Zhang, X. and Georges, A. 2015. Sex reversal triggers the rapid transition from genetic to temperature-dependent sex. Nature 523:79-82. [pdf]

Janes, D.E., Organ, C.L., Stiglec, R., O'Meally, D.O., Sarre, S.D., Georges, A., Graves, J.A.M., Valenzuela, N., Literman, R.A., Rutherford, K., Gemmell, N., Iverson, J.B., Tamplin, J.W., Edwards, S.V. and Ezaz, T.E. 2014. Molecular evolution of Dmrt1 accompanies change of sex determining mechanisms in Reptilia. Biology Letters 10:20140809. [pdf]

Matsubara K., Gamble T., Matsuda Y., Zarkower D., Sarre S., Georges A., Marshal Graves J. and Ezaz T. 2014. Non-homologous sex chromosomes in two geckos (Gekkonidae: Gekkota) with female heterogamety. Cytogenetic and Genome Research 143:251-258. [pdf]

Ezaz, T., Azad, B., O'Meally, D., Young, M.J., Matsubara, K., Edwards, M.J., Zhang, X., Holleley, C.E., Deakin, J.E., Marshall-Graves, J.A., Georges, A., Edwards, S.V. and Sarre, S.D. 2013. Sequence and gene content of a large fragment of a lizard sex chromosome and evaluation of candidate sex differentiating gene R-spondin1. BMC Genomics 14, 899. [pdf]

Schwanz, L.E., Ezaz, T., Gruber, B. and Georges, A. 2013. Novel evolutionary pathways of sex determining mechanisms. Journal of Evolutionary Biology 26:2544-2557. [pdf]

Young, M.J., O'Meally, D., Sarre, S.D., Georges, A. and Ezaz, T. 2013. Molecular cytogenetic map of the central bearded dragon Pogona vitticeps (Squamata: Agamidae). Chromosome Research 21:361-374. [pdf]

Frere, C.H., Prentis, P.J., Ezaz, T. and Georges, A. 2012. Isolation and characterisation of novel microsatellite and mitochondrial DNA markers for the Eastern Water Dragon (Physignathus lesueurii). Conservation Genetics Resources 4:13-116. [pdf]

O'Meally, D., Ezaz, T., Georges, A., Sarre, S.D. and Graves, J.A.M. 2012. Are some chromosomes particularly good at sex? Insights from amniotes. Chromosome Research 20:7-19. [pdf]

O'Meally, D., Ezaz, T., Sarre, S.D., Georges, A. and Marshall-Graves, J.A. 2012. What makes some chromosomes good at sex. Pp. 58-59 in Proceedings of the 6th International Symposium on the Biology Vertebrate Sex Determination, Kona, Hawaii, April 23-27, 2012.

Quinn, A.E., Sarre, S.D., Ezaz, T., Graves, J.A.M. and Georges, A. 2011. Evolutionary transitions between mechanisms of sex determination in vertebrates. Biology Letters 7:443-448 [pdf]

Sarre, S.D., Ezaz, T. and Georges, A. 2011. Transitions between sex determining systems in reptiles and amphibians. Annual Review of Genomics and Human Genetics 12:391-406. [pdf]

Ezaz, T., Sarre, S.D., O'Meally, D., Graves, J.A.M. and Georges, A. 2010. Sex chromosome evolution in lizards: independent origins and rapid transitions. Cytogenetic and Genome Research 127:249-260. [pdf]

Georges, A., Ezaz, T., Quinn, A.E. and Sarre, S.D. 2010. Are reptiles predisposed to temperature-dependent sex determination? Sexual Development 4:7-15 [pdf]

O'Meally, D., Patel, H.R., Stiglec, R., Sarre, S.D., Georges, A., Graves, J.A.M. and Ezaz, T. 2010. Non-homologous sex chromosomes of birds and snakes share repetitive sequences. Chromosome Research 18:787-800. [pdf]

Quinn, A.E., Ezaz, T., Sarre, S.D., Graves, J.A.M. and Georges, A. 2010. Extension, single-locus conversion and physical mapping of sex chromosome sequences identify the Z microchromosome and pseudo-autosomal region in a dragon lizard, Pogona vitticeps. Heredity 104:410-417 [pdf]

Ezaz, T., Moritz, B., Waters, P.D., Graves, J.A.M., Georges, A. and Sarre, S.D. 2009. The ZW sex microchromosomes of an Australian dragon lizard share no homology with those of other reptiles or birds. Chromosome Research 17:965-973 [pdf]

Ezaz, T., Quinn, T.E., Sarre, S.D., O'Meally, D., Georges, A., and Graves, J.A.M. 2009. Molecular marker suggests rapid changes of sex-determining mechanisms in Australian dragon lizards. Chromosome Research 17:91-98. [pdf]

Ezaz, T., O'Meally, D., Quinn, A.E., Sarre, S.D., Georges, A. and Graves, J.A.M. 2008. A simple non-invasive protocol to establish primary cell lines from tail and toe explants for cytogenetic studies in Australian dragon lizards (Squamata: Agamidae). Cytotechnology 58:135-139 [pdf]

Quinn, A.E., Georges, A., Sarre, S.D., Guarino, F., Ezaz, T., and Graves, J.A.M. 2007. Temperature sex reversal implies sex gene dosage in a reptile. Science 316:411, plus supplement. [pdf]

Ezaz, T., Quinn, A.E., Miura, I., Sarre, S.D., Georges, A. and Graves, J.A.M. 2005. The dragon lizard Pogona vitticeps has ZZ/ZW micro-sex chromosomes. Chromosome Research 13:763-776. [pdf]

Georges, A., Doody, J.S., Beggs, K. and Young J.E. 2004. Thermal models of TSD under laboratory and field conditions. Pp. 79-89 in Valenzuela, N. and Lance, V. (Eds). Temperature dependent sex determination in reptiles. Smithsonian Institute, Washington. [pdf]

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