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McLaughlin JF, Brock KM, Gates I, Pethkar A, Piattoni M, Rossi A, Lipshutz SE. Multivariate Models of Animal Sex: Breaking Binaries Leads to a Better Understanding of Ecology and Evolution. Integr Comp Biol 2023; 63:891-906. [PMID: 37156506 PMCID: PMC10563656 DOI: 10.1093/icb/icad027] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/28/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023] Open
Abstract
"Sex" is often used to describe a suite of phenotypic and genotypic traits of an organism related to reproduction. However, these traits-gamete type, chromosomal inheritance, physiology, morphology, behavior, etc.-are not necessarily coupled, and the rhetorical collapse of variation into a single term elides much of the complexity inherent in sexual phenotypes. We argue that consideration of "sex" as a constructed category operating at multiple biological levels opens up new avenues for inquiry in our study of biological variation. We apply this framework to three case studies that illustrate the diversity of sex variation, from decoupling sexual phenotypes to the evolutionary and ecological consequences of intrasexual polymorphisms. We argue that instead of assuming binary sex in these systems, some may be better categorized as multivariate and nonbinary. Finally, we conduct a meta-analysis of terms used to describe diversity in sexual phenotypes in the scientific literature to highlight how a multivariate model of sex can clarify, rather than cloud, studies of sexual diversity within and across species. We argue that such an expanded framework of "sex" better equips us to understand evolutionary processes, and that as biologists, it is incumbent upon us to push back against misunderstandings of the biology of sexual phenotypes that enact harm on marginalized communities.
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Affiliation(s)
- J F McLaughlin
- Department of Environmental Science, Policy, and Management, College of Natural Resources, University of California, Berkeley, CA 94720, USA
| | - Kinsey M Brock
- Department of Environmental Science, Policy, and Management, College of Natural Resources, University of California, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Isabella Gates
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Anisha Pethkar
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Marcus Piattoni
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Alexis Rossi
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Sara E Lipshutz
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
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Wagner S, Whiteley SL, Castelli M, Patel HR, Deveson IW, Blackburn J, Holleley CE, Marshall Graves JA, Georges A. Gene expression of male pathway genes sox9 and amh during early sex differentiation in a reptile departs from the classical amniote model. BMC Genomics 2023; 24:243. [PMID: 37147622 PMCID: PMC10163765 DOI: 10.1186/s12864-023-09334-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
BACKGROUND Sex determination is the process whereby the bipotential embryonic gonads become committed to differentiate into testes or ovaries. In genetic sex determination (GSD), the sex determining trigger is encoded by a gene on the sex chromosomes, which activates a network of downstream genes; in mammals these include SOX9, AMH and DMRT1 in the male pathway, and FOXL2 in the female pathway. Although mammalian and avian GSD systems have been well studied, few data are available for reptilian GSD systems. RESULTS We conducted an unbiased transcriptome-wide analysis of gonad development throughout differentiation in central bearded dragon (Pogona vitticeps) embryos with GSD. We found that sex differentiation of transcriptomic profiles occurs at a very early stage, before the gonad consolidates as a body distinct from the gonad-kidney complex. The male pathway genes dmrt1 and amh and the female pathway gene foxl2 play a key role in early sex differentiation in P. vitticeps, but the central player of the mammalian male trajectory, sox9, is not differentially expressed in P. vitticeps at the bipotential stage. The most striking difference from GSD systems of other amniotes is the high expression of the male pathway genes amh and sox9 in female gonads during development. We propose that a default male trajectory progresses if not repressed by a W-linked dominant gene that tips the balance of gene expression towards the female trajectory. Further, weighted gene expression correlation network analysis revealed novel candidates for male and female sex differentiation. CONCLUSION Our data reveal that interpretation of putative mechanisms of GSD in reptiles cannot solely depend on lessons drawn from mammals.
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Affiliation(s)
- Susan Wagner
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
| | - Sarah L Whiteley
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
- Australian National Wildlife Collection CSIRO, National Research Collections Australia, Crace, ACT, Australia
| | - Meghan Castelli
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
- Australian National Wildlife Collection CSIRO, National Research Collections Australia, Crace, ACT, Australia
| | - Hardip R Patel
- Genome Sciences Department. John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Ira W Deveson
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - James Blackburn
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Clare E Holleley
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
- Australian National Wildlife Collection CSIRO, National Research Collections Australia, Crace, ACT, Australia
| | - Jennifer A Marshall Graves
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
- School of Life Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia.
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McLaughlin JF, Aguilar C, Bernstein JM, Navia-Gine WG, Cueto-Aparicio LE, Alarcon AC, Alarcon BD, Collier R, Takyar A, Vong SJ, López-Chong OG, Driver R, Loaiza JR, De León LF, Saltonstall K, Lipshutz SE, Arcila D, Brock KM, Miller MJ. Comparative phylogeography reveals widespread cryptic diversity driven by ecology in Panamanian birds. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023. [PMID: 36993716 DOI: 10.1101/2023.01.26.525769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
UNLABELLED Widespread species often harbor unrecognized genetic diversity, and investigating the factors associated with such cryptic variation can help us better understand the forces driving diversification. Here, we identify potential cryptic species based on a comprehensive dataset of COI mitochondrial DNA barcodes from 2,333 individual Panamanian birds across 429 species, representing 391 (59%) of the 659 resident landbird species of the country, as well as opportunistically sampled waterbirds. We complement this dataset with additional publicly available mitochondrial loci, such as ND2 and cytochrome b, obtained from whole mitochondrial genomes from 20 taxa. Using barcode identification numbers (BINs), we find putative cryptic species in 19% of landbird species, highlighting hidden diversity in the relatively well-described avifauna of Panama. Whereas some of these mitochondrial divergence events corresponded with recognized geographic features that likely isolated populations, such as the Cordillera Central highlands, the majority (74%) of lowland splits were between eastern and western populations. The timing of these splits are not temporally coincident across taxa, suggesting that historical events, such as the formation of the Isthmus of Panama and Pleistocene climatic cycles, were not the primary drivers of cryptic diversification. Rather, we observed that forest species, understory species, insectivores, and strongly territorial species-all traits associated with lower dispersal ability-were all more likely to have multiple BINs in Panama, suggesting strong ecological associations with cryptic divergence. Additionally, hand-wing index, a proxy for dispersal capability, was significantly lower in species with multiple BINs, indicating that dispersal ability plays an important role in generating diversity in Neotropical birds. Together, these results underscore the need for evolutionary studies of tropical bird communities to consider ecological factors along with geographic explanations, and that even in areas with well-known avifauna, avian diversity may be substantially underestimated. LAY SUMMARY - What factors are common among bird species with cryptic diversity in Panama? What role do geography, ecology, phylogeographic history, and other factors play in generating bird diversity?- 19% of widely-sampled bird species form two or more distinct DNA barcode clades, suggesting widespread unrecognized diversity.- Traits associated with reduced dispersal ability, such as use of forest understory, high territoriality, low hand-wing index, and insectivory, were more common in taxa with cryptic diversity. Filogeografía comparada revela amplia diversidad críptica causada por la ecología en las aves de Panamá. RESUMEN Especies extendidas frecuentemente tiene diversidad genética no reconocida, y investigando los factores asociados con esta variación críptica puede ayudarnos a entender las fuerzas que impulsan la diversificación. Aquí, identificamos especies crípticas potenciales basadas en un conjunto de datos de códigos de barras de ADN mitocondrial de 2,333 individuos de aves de Panama en 429 especies, representando 391 (59%) de las 659 especies de aves terrestres residentes del país, además de algunas aves acuáticas muestreada de manera oportunista. Adicionalmente, complementamos estos datos con secuencias mitocondriales disponibles públicamente de otros loci, tal como ND2 o citocroma b, obtenidos de los genomas mitocondriales completos de 20 taxones. Utilizando los números de identificación de código de barras (en ingles: BINs), un sistema taxonómico numérico que proporcina una estimación imparcial de la diversidad potencial a nivel de especie, encontramos especies crípticas putativas en 19% de las especies de aves terrestres, lo que destaca la diversidad oculta en la avifauna bien descrita de Panamá. Aunque algunos de estos eventos de divergencia conciden con características geográficas que probablemente aislaron las poblaciones, la mayoría (74%) de la divergencia en las tierras bajas se encuentra entre las poblaciones orientales y occidentales. El tiempo de esta divergencia no coincidió entre los taxones, sugiriendo que eventos históricos tales como la formación del Istmo de Panamá y los ciclos climáticos del pleistoceno, no fueron los principales impulsores de la especiación. En cambio, observamos asociaciones fuertes entre las características ecológicas y la divergencia mitocondriale: las especies del bosque, sotobosque, con una dieta insectívora, y con territorialidad fuerte mostraton múltiple BINs probables. Adicionalmente, el índice mano-ala, que está asociado a la capacidad de dispersión, fue significativamente menor en las especies con BINs multiples, sugiriendo que la capacidad de dispersión tiene un rol importamente en la generación de la diversidad de las aves neotropicales. Estos resultos demonstran la necesidad de que estudios evolutivos de las comunidades de aves tropicales consideren los factores ecológicos en conjunto con las explicaciones geográficos. Palabras clave: biodiversidad tropical, biogeografía, códigos de barras, dispersión, especies crípticas.
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Whiteley SL, Holleley CE, Georges A. Developmental dynamics of sex reprogramming by high incubation temperatures in a dragon lizard. BMC Genomics 2022; 23:322. [PMID: 35459109 PMCID: PMC9034607 DOI: 10.1186/s12864-022-08544-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 04/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In some vertebrate species, gene-environment interactions can determine sex, driving bipotential gonads to differentiate into either ovaries or testes. In the central bearded dragon (Pogona vitticeps), the genetic influence of sex chromosomes (ZZ/ZW) can be overridden by high incubation temperatures, causing ZZ male to female sex reversal. Previous research showed ovotestes, a rare gonadal phenotype with traits of both sexes, develop during sex reversal, leading to the hypothesis that sex reversal relies on high temperature feminisation to outcompete the male genetic cue. To test this, we conducted temperature switching experiments at key developmental stages, and analysed the effect on gonadal phenotypes using histology and transcriptomics. RESULTS We found sexual fate is more strongly influenced by the ZZ genotype than temperature. Any exposure to low temperatures (28 °C) caused testes differentiation, whereas sex reversal required longer exposure to high temperatures. We revealed ovotestes exist along a spectrum of femaleness to male-ness at the transcriptional level. We found inter-individual variation in gene expression changes following temperature switches, suggesting both genetic sensitivity to, and the timing and duration of the temperature cue influences sex reversal. CONCLUSIONS These findings bring new insights to the mechanisms underlying sex reversal, improving our understanding of thermosensitive sex systems in vertebrates.
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Affiliation(s)
- Sarah L Whiteley
- Institute for Applied Ecology, University of Canberra, Canberra, Australia.
- Australian National Wildlife Collection, CSIRO, Canberra, Australia.
| | - Clare E Holleley
- Australian National Wildlife Collection, CSIRO, Canberra, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
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Whiteley SL, Wagner S, Holleley CE, Deveson IW, Marshall Graves JA, Georges A. Truncated jarid2 and kdm6b transcripts are associated with temperature-induced sex reversal during development in a dragon lizard. SCIENCE ADVANCES 2022; 8:eabk0275. [PMID: 35442724 PMCID: PMC9020659 DOI: 10.1126/sciadv.abk0275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 03/04/2022] [Indexed: 05/23/2023]
Abstract
Sex determination and differentiation in reptiles are complex. In the model species, Pogona vitticeps, high incubation temperature can cause male to female sex reversal. To elucidate the epigenetic mechanisms of thermolabile sex, we used an unbiased genome-wide assessment of intron retention during sex reversal. The previously implicated chromatin modifiers (jarid2 and kdm6b) were two of three genes to display sex reversal-specific intron retention. In these species, embryonic intron retention resulting in C-terminally truncated jarid2 and kdm6b isoforms consistently occurs at low temperatures. High-temperature sex reversal is uniquely characterized by a high prevalence of N-terminally truncated isoforms of jarid2 and kdm6b, which are not present at low temperatures, or in two other reptiles with temperature-dependent sex determination. This work verifies that chromatin-modifying genes are involved in highly conserved temperature responses and can also be transcribed into isoforms with new sex-determining roles.
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Affiliation(s)
- Sarah L. Whiteley
- Institute for Applied Ecology, University of Canberra, Bruce, Australia
- Australian National Wildlife Collection, CSIRO National Research Collections Australia, Canberra, Australia
| | - Susan Wagner
- Institute for Applied Ecology, University of Canberra, Bruce, Australia
| | - Clare E. Holleley
- Australian National Wildlife Collection, CSIRO National Research Collections Australia, Canberra, Australia
| | - Ira W. Deveson
- Garvan Institute of Medical Research, Sydney, Australia
- St. Vincent’s Clinical School, UNSW, Sydney, Australia
| | | | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Bruce, Australia
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6
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Whiteley SL, Holleley CE, Wagner S, Blackburn J, Deveson IW, Marshall Graves JA, Georges A. Two transcriptionally distinct pathways drive female development in a reptile with both genetic and temperature dependent sex determination. PLoS Genet 2021; 17:e1009465. [PMID: 33857129 PMCID: PMC8049264 DOI: 10.1371/journal.pgen.1009465] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/03/2021] [Indexed: 12/19/2022] Open
Abstract
How temperature determines sex remains unknown. A recent hypothesis proposes that conserved cellular mechanisms (calcium and redox; 'CaRe' status) sense temperature and identify genes and regulatory pathways likely to be involved in driving sexual development. We take advantage of the unique sex determining system of the model organism, Pogona vitticeps, to assess predictions of this hypothesis. P. vitticeps has ZZ male: ZW female sex chromosomes whose influence can be overridden in genetic males by high temperatures, causing male-to-female sex reversal. We compare a developmental transcriptome series of ZWf females and temperature sex reversed ZZf females. We demonstrate that early developmental cascades differ dramatically between genetically driven and thermally driven females, later converging to produce a common outcome (ovaries). We show that genes proposed as regulators of thermosensitive sex determination play a role in temperature sex reversal. Our study greatly advances the search for the mechanisms by which temperature determines sex.
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Affiliation(s)
- Sarah L. Whiteley
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
- Australian National Wildlife Collection CSIRO National Research Collections Australia, Canberra, Australia
| | - Clare E. Holleley
- Australian National Wildlife Collection CSIRO National Research Collections Australia, Canberra, Australia
| | - Susan Wagner
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
| | - James Blackburn
- Garvan Institute of Medical Research, Sydney, Australia
- St. Vincent’s Clinical School, UNSW, Sydney, Australia
| | - Ira W. Deveson
- Garvan Institute of Medical Research, Sydney, Australia
- St. Vincent’s Clinical School, UNSW, Sydney, Australia
| | - Jennifer A. Marshall Graves
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
- Latrobe University, Melbourne, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
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Okuyama K, Sakuma Y, Sasaki T. Post-Ovipositional Developmental Stages of the Japanese Grass Lizard, Takydromus tachydromoides (Squamata: Lacertidae). CURRENT HERPETOLOGY 2021. [DOI: 10.5358/hsj.40.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Kentaro Okuyama
- Department of Human and Animal-Plant Relationships, Graduate School of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243–0034, JAPAN
| | - Yume Sakuma
- Department of Human and Animal-Plant Relationships, Graduate School of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243–0034, JAPAN
| | - Takeshi Sasaki
- Department of Human and Animal-Plant Relationships, Graduate School of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243–0034, JAPAN
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Whiteley SL, Georges A, Weisbecker V, Schwanz LE, Holleley CE. Ovotestes suggest cryptic genetic influence in a reptile model for temperature-dependent sex determination. Proc Biol Sci 2021; 288:20202819. [PMID: 33467998 DOI: 10.1098/rspb.2020.2819] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sex determination and differentiation in reptiles is complex. Temperature-dependent sex determination (TSD), genetic sex determination (GSD) and the interaction of both environmental and genetic cues (sex reversal) can drive the development of sexual phenotypes. The jacky dragon (Amphibolurus muricatus) is an attractive model species for the study of gene-environment interactions because it displays a form of Type II TSD, where female-biased sex ratios are observed at extreme incubation temperatures and approximately 50 : 50 sex ratios occur at intermediate temperatures. This response to temperature has been proposed to occur due to underlying sex determining loci, the influence of which is overridden at extreme temperatures. Thus, sex reversal at extreme temperatures is predicted to produce the female-biased sex ratios observed in A. muricatus. The occurrence of ovotestes during development is a cellular marker of temperature sex reversal in a closely related species Pogona vitticeps. Here, we present the first developmental data for A. muricatus, and show that ovotestes occur at frequencies consistent with a mode of sex determination that is intermediate between GSD and TSD. This is the first evidence suggestive of underlying unidentified sex determining loci in a species that has long been used as a model for TSD.
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Affiliation(s)
- Sarah L Whiteley
- Institute for Applied Ecology, University of Canberra, Canberra, Australia.,Australian National Wildlife Collection, CSIRO, Canberra, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
| | - Vera Weisbecker
- College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Lisa E Schwanz
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, UNSW, Sydney, Australia
| | - Clare E Holleley
- Australian National Wildlife Collection, CSIRO, Canberra, Australia
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Castelli M, Georges A, Holleley CE. Corticosterone does not have a role in temperature sex reversal in the central bearded dragon (Pogona vitticeps). JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:301-310. [PMID: 33411403 DOI: 10.1002/jez.2441] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/30/2020] [Accepted: 12/18/2020] [Indexed: 12/29/2022]
Abstract
Environmental sex determination (ESD) is common among ectothermic vertebrates. The stress axis and production of stress hormones (corticosteroids) regulates ESD in fish, but evidence of a similar influence in reptiles is sparse and conflicting. The central bearded dragon (Pogona vitticeps) has a system of sex determination involving the interplay between sex chromosomes (ZZ/ZW female heterogamety) and the thermal environment. High egg incubation temperatures induce sex reversal of the ZZ genotype, feminizing chromosomally male individuals. Here we show that corticosterone elevation is not associated with sex reversal in the central bearded dragon, either during embryonic development or adulthood. We also demonstrate experimentally that sex determination is not affected by corticosterone injection into the yolk. This strongly suggests that stress axis upregulation by high temperature during incubation does not cause sex reversal in P. vitticeps. Our work is in general agreement with other research in reptiles, which suggests that the stress axis does not mediate sex in reptiles with ESD. Alternative biological systems may be responsible for capturing environmental conditions during reptile development, such as cellular calcium and redox regulation or the action of temperature-sensitive splicing factors.
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Affiliation(s)
- Meghan Castelli
- Institute for Applied Ecology, University of Canberra, Canberra, Australia.,Australian National Wildlife Collection, CSIRO, Canberra, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
| | - Clare E Holleley
- Institute for Applied Ecology, University of Canberra, Canberra, Australia.,Australian National Wildlife Collection, CSIRO, Canberra, Australia
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Castelli MA, Georges A, Cherryh C, Rosauer DF, Sarre SD, Contador‐Kelsall I, Holleley CE. Evolving thermal thresholds explain the distribution of temperature sex reversal in an Australian dragon lizard. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13203] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Meghan A. Castelli
- Institute for Applied Ecology University of Canberra Canberra Australian Capital Territory Australia
- Australian National Wildlife CollectionCSIRO National Research Collections Australia Canberra Australian Capital Territory Australia
| | - Arthur Georges
- Institute for Applied Ecology University of Canberra Canberra Australian Capital Territory Australia
| | - Caitlin Cherryh
- Australian National Wildlife CollectionCSIRO National Research Collections Australia Canberra Australian Capital Territory Australia
- Department of Ecology and Evolution Research School of Biology Australian National University Canberra Australian Capital Territory Australia
| | - Dan F. Rosauer
- Department of Ecology and Evolution Research School of Biology Australian National University Canberra Australian Capital Territory Australia
| | - Stephen D. Sarre
- Institute for Applied Ecology University of Canberra Canberra Australian Capital Territory Australia
| | - Isabella Contador‐Kelsall
- School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong New South Wales Australia
| | - Clare E. Holleley
- Institute for Applied Ecology University of Canberra Canberra Australian Capital Territory Australia
- Australian National Wildlife CollectionCSIRO National Research Collections Australia Canberra Australian Capital Territory Australia
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11
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Dissanayake DSB, Holleley CE, Hill LK, O'Meally D, Deakin JE, Georges A. Identification of Y chromosome markers in the eastern three-lined skink (Bassiana duperreyi) using in silico whole genome subtraction. BMC Genomics 2020; 21:667. [PMID: 32993477 PMCID: PMC7526180 DOI: 10.1186/s12864-020-07071-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022] Open
Abstract
Background Homologous sex chromosomes can differentiate over time because recombination is suppressed in the region of the sex determining locus, leading to the accumulation of repeats, progressive loss of genes that lack differential influence on the sexes and sequence divergence on the hemizygous homolog. Divergence in the non-recombining regions leads to the accumulation of Y or W specific sequence useful for developing sex-linked markers. Here we use in silico whole-genome subtraction to identify putative sex-linked sequences in the scincid lizard Bassiana duperreyi which has heteromorphic XY sex chromosomes. Results We generated 96.7 × 109 150 bp paired-end genomic sequence reads from a XY male and 81.4 × 109 paired-end reads from an XX female for in silico whole genome subtraction to yield Y enriched contigs. We identified 7 reliable markers which were validated as Y chromosome specific by polymerase chain reaction (PCR) against a panel of 20 males and 20 females. Conclusions The sex of B. duperreyi can be reversed by low temperatures (XX genotype reversed to a male phenotype). We have developed sex-specific markers to identify the underlying genotypic sex and its concordance or discordance with phenotypic sex in wild populations of B. duperreyi. Our pipeline can be applied to isolate Y or W chromosome-specific sequences of any organism and is not restricted to sequence residing within single-copy genes. This study greatly improves our knowledge of the Y chromosome in B. duperreyi and will enhance future studies of reptile sex determination and sex chromosome evolution.
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Affiliation(s)
- Duminda Sampath Bandara Dissanayake
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.,Australian National Wildlife Collection, CSIRO, Canberra, ACT, 2911, Australia
| | - Clare Ellen Holleley
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.,Australian National Wildlife Collection, CSIRO, Canberra, ACT, 2911, Australia
| | - Laura Kate Hill
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
| | - Denis O'Meally
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.,Present Address: Centre for Gene Therapy, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Janine Eileen Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
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12
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Van Dyke JU, Thompson MB, Burridge CP, Castelli MA, Clulow S, Dissanayake DSB, Dong CM, Doody JS, Edwards DL, Ezaz T, Friesen CR, Gardner MG, Georges A, Higgie M, Hill PL, Holleley CE, Hoops D, Hoskin CJ, Merry DL, Riley JL, Wapstra E, While GM, Whiteley SL, Whiting MJ, Zozaya SM, Whittington CM. Australian lizards are outstanding models for reproductive biology research. AUST J ZOOL 2020. [DOI: 10.1071/zo21017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Australian lizards are a diverse group distributed across the continent and inhabiting a wide range of environments. Together, they exhibit a remarkable diversity of reproductive morphologies, physiologies, and behaviours that is broadly representative of vertebrates in general. Many reproductive traits exhibited by Australian lizards have evolved independently in multiple lizard lineages, including sociality, complex signalling and mating systems, viviparity, and temperature-dependent sex determination. Australian lizards are thus outstanding model organisms for testing hypotheses about how reproductive traits function and evolve, and they provide an important basis of comparison with other animals that exhibit similar traits. We review how research on Australian lizard reproduction has contributed to answering broader evolutionary and ecological questions that apply to animals in general. We focus on reproductive traits, processes, and strategies that are important areas of current research, including behaviours and signalling involved in courtship; mechanisms involved in mating, egg production, and sperm competition; nesting and gestation; sex determination; and finally, birth in viviparous species. We use our review to identify important questions that emerge from an understanding of this body of research when considered holistically. Finally, we identify additional research questions within each topic that Australian lizards are well suited for reproductive biologists to address.
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13
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Griffing AH, Sanger TJ, Daza JD, Nielsen SV, Pinto BJ, Stanley EL, Gamble T. Embryonic development of a parthenogenetic vertebrate, the mourning gecko (
Lepidodactylus lugubris
). Dev Dyn 2019; 248:1070-1090. [DOI: 10.1002/dvdy.72] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Aaron H. Griffing
- Department of Biological SciencesMarquette University Milwaukee Wisconsin
| | - Thomas J. Sanger
- Department of BiologyLoyola University in Chicago Chicago Illinois
| | - Juan D. Daza
- Department of Biological SciencesSam Houston State University Huntsville Texas
| | - Stuart V. Nielsen
- Department of HerpetologyFlorida Museum of Natural History Gainesville Florida
| | - Brendan J. Pinto
- Department of Biological SciencesMarquette University Milwaukee Wisconsin
| | - Edward L. Stanley
- Department of HerpetologyFlorida Museum of Natural History Gainesville Florida
| | - Tony Gamble
- Department of Biological SciencesMarquette University Milwaukee Wisconsin
- Milwaukee Public Museum Milwaukee Wisconsin
- Bell Museum of Natural HistoryUniversity of Minnesota Saint Paul Minnesota
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14
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Developmental asynchrony and antagonism of sex determination pathways in a lizard with temperature-induced sex reversal. Sci Rep 2018; 8:14892. [PMID: 30291276 PMCID: PMC6173690 DOI: 10.1038/s41598-018-33170-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/19/2018] [Indexed: 12/22/2022] Open
Abstract
Vertebrate sex differentiation follows a conserved suite of developmental events: the bipotential gonads differentiate and shortly thereafter sex specific traits become dimorphic. However, this may not apply to squamates, a diverse vertebrate lineage comprising of many species with thermosensitive sexual development. Of the three species with data on the relative timing of gonad differentiation and genital dimorphism, the females of two (Niveoscincus ocellatus and Barisia imbricata) exhibit a phase of temporary pseudohermaphroditism or TPH (gonads have differentiated well before genital dimorphism). We report a third example of TPH in Pogona vitticeps, an agamid with temperature-induced male to female sex reversal. These findings suggest that for female squamates, genital and gonad development may not be closely synchronised, so that TPH may be common. We further observed a high frequency of ovotestes, a usually rare gonadal phenotype characterised by a mix of male and female structures, exclusively associated with temperature-induced sex reversal. We propose that ovotestes are evidence of a period of antagonism between male and female sex-determining pathways during sex reversal. Female sexual development in squamates is considerably more complex than has been appreciated, providing numerous avenues for future exploration of the genetic and hormonal cues that govern sexual development.
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15
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Sanger TJ, Kyrkos J, Lachance DJ, Czesny B, Stroud JT. The effects of thermal stress on the early development of the lizard Anolis sagrei. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:244-251. [DOI: 10.1002/jez.2185] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 04/20/2018] [Accepted: 04/26/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Thomas J. Sanger
- Department of Biology; Loyola University Chicago; Chicago Illinois
| | - Judith Kyrkos
- Department of Biology; Loyola University Chicago; Chicago Illinois
| | | | - Beata Czesny
- Department of Biology; Loyola University Chicago; Chicago Illinois
| | - James T. Stroud
- Dept. of Biological Sciences; Florida International University; Miami Florida
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16
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Ollonen J, Da Silva FO, Mahlow K, Di-Poï N. Skull Development, Ossification Pattern, and Adult Shape in the Emerging Lizard Model Organism Pogona vitticeps: A Comparative Analysis With Other Squamates. Front Physiol 2018; 9:278. [PMID: 29643813 PMCID: PMC5882870 DOI: 10.3389/fphys.2018.00278] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/08/2018] [Indexed: 12/02/2022] Open
Abstract
The rise of the Evo-Devo field and the development of multidisciplinary research tools at various levels of biological organization have led to a growing interest in researching for new non-model organisms. Squamates (lizards and snakes) are particularly important for understanding fundamental questions about the evolution of vertebrates because of their high diversity and evolutionary innovations and adaptations that portrait a striking body plan change that reached its extreme in snakes. Yet, little is known about the intricate connection between phenotype and genotype in squamates, partly due to limited developmental knowledge and incomplete characterization of embryonic development. Surprisingly, squamate models have received limited attention in comparative developmental studies, and only a few species examined so far can be considered as representative and appropriate model organism for mechanistic Evo-Devo studies. Fortunately, the agamid lizard Pogona vitticeps (central bearded dragon) is one of the most popular, domesticated reptile species with both a well-established history in captivity and key advantages for research, thus forming an ideal laboratory model system and justifying his recent use in reptile biology research. We first report here the complete post-oviposition embryonic development for P. vitticeps based on standardized staging systems and external morphological characters previously defined for squamates. Whereas the overall morphological development follows the general trends observed in other squamates, our comparisons indicate major differences in the developmental sequence of several tissues, including early craniofacial characters. Detailed analysis of both embryonic skull development and adult skull shape, using a comparative approach integrating CT-scans and gene expression studies in P. vitticeps as well as comparative embryology and 3D geometric morphometrics in a large dataset of lizards and snakes, highlights the extreme adult skull shape of P. vitticeps and further indicates that heterochrony has played a key role in the early development and ossification of squamate skull bones. Such detailed studies of embryonic character development, craniofacial patterning, and bone formation are essential for the establishment of well-selected squamate species as Evo-Devo model organisms. We expect that P. vitticeps will continue to emerge as a new attractive model organism for understanding developmental and molecular processes underlying tissue formation, morphology, and evolution.
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Affiliation(s)
- Joni Ollonen
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Filipe O. Da Silva
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kristin Mahlow
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Nicolas Di-Poï
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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17
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Cavoto E, Neuenschwander S, Goudet J, Perrin N. Sex-antagonistic genes, XY recombination and feminized Y chromosomes. J Evol Biol 2018; 31:416-427. [DOI: 10.1111/jeb.13235] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 01/20/2023]
Affiliation(s)
- E. Cavoto
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
| | - S. Neuenschwander
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
- Vital-IT; Swiss Institute of Bioinformatics; Lausanne Switzerland
| | - J. Goudet
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
- Swiss Institute of Bioinformatics; Lausanne Switzerland
| | - N. Perrin
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
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