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Stringer EJ, Gruber B, Sarre SD, Wardle GM, Edwards SV, Dickman CR, Greenville AC, Duncan RP. Boom-bust population dynamics drive rapid genetic change. Proc Natl Acad Sci U S A 2024; 121:e2320590121. [PMID: 38621118 PMCID: PMC11067018 DOI: 10.1073/pnas.2320590121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/06/2024] [Indexed: 04/17/2024] Open
Abstract
Increasing environmental threats and more extreme environmental perturbations place species at risk of population declines, with associated loss of genetic diversity and evolutionary potential. While theory shows that rapid population declines can cause loss of genetic diversity, populations in some environments, like Australia's arid zone, are repeatedly subject to major population fluctuations yet persist and appear able to maintain genetic diversity. Here, we use repeated population sampling over 13 y and genotype-by-sequencing of 1903 individuals to investigate the genetic consequences of repeated population fluctuations in two small mammals in the Australian arid zone. The sandy inland mouse (Pseudomys hermannsburgensis) experiences marked boom-bust population dynamics in response to the highly variable desert environment. We show that heterozygosity levels declined, and population differentiation (FST) increased, during bust periods when populations became small and isolated, but that heterozygosity was rapidly restored during episodic population booms. In contrast, the lesser hairy-footed dunnart (Sminthopsis youngsoni), a desert marsupial that maintains relatively stable population sizes, showed no linear declines in heterozygosity. These results reveal two contrasting ways in which genetic diversity is maintained in highly variable environments. In one species, diversity is conserved through the maintenance of stable population sizes across time. In the other species, diversity is conserved through rapid genetic mixing during population booms that restores heterozygosity lost during population busts.
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Affiliation(s)
- Emily J. Stringer
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, CanberraACT2617, Australia
| | - Bernd Gruber
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, CanberraACT2617, Australia
| | - Stephen D. Sarre
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, CanberraACT2617, Australia
| | - Glenda M. Wardle
- Desert Ecology Research Group, School of Life and Environmental Sciences, The University of Sydney, SydneyNSW2006, Australia
| | - Scott V. Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA02138
| | - Christopher R. Dickman
- Desert Ecology Research Group, School of Life and Environmental Sciences, The University of Sydney, SydneyNSW2006, Australia
| | - Aaron C. Greenville
- Desert Ecology Research Group, School of Life and Environmental Sciences, The University of Sydney, SydneyNSW2006, Australia
| | - Richard P. Duncan
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, CanberraACT2617, Australia
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Wild KH, Roe JH, Schwanz L, Rodgers E, Dissanayake DSB, Georges A, Sarre SD, Noble DWA. Metabolic consequences of sex reversal in two lizard species: a test of the like-genotype and like-phenotype hypotheses. J Exp Biol 2023; 226:jeb245657. [PMID: 37309620 PMCID: PMC10357012 DOI: 10.1242/jeb.245657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/05/2023] [Indexed: 06/14/2023]
Abstract
Vertebrate sex is typically determined genetically, but in many ectotherms sex can be determined by genes (genetic sex determination, GSD), temperature (temperature-dependent sex determination, TSD), or interactions between genes and temperature during development. TSD may involve GSD systems with either male or female heterogamety (XX/XY or ZZ/ZW) where temperature overrides chromosomal sex determination to cause a mismatch between genetic sex and phenotypic sex (sex reversal). In these temperature-sensitive lineages, phylogenetic investigations point to recurrent evolutionary shifts between genotypic and temperature-dependent sex determination. These evolutionary transitions in sex determination can occur rapidly if selection favours the reversed sex over the concordant phenotypic sex. To investigate the consequences of sex reversal on offspring phenotypes, we measured two energy-driven traits (metabolism and growth) and 6 month survival in two species of reptile with different patterns of temperature-induced sex reversal. Male sex reversal occurs in Bassiana duperreyi when chromosomal females (female XX) develop male phenotypes (maleSR XX), while female sex reversal occurs in Pogona vitticeps when chromosomal males (male ZZ) develop female phenotypes (femaleSR ZZ). We show metabolism in maleSR XX was like that of male XY; that is, reflective of phenotypic sex and lower than genotypic sex. In contrast, for Pogona vitticeps, femaleSR ZZ metabolism was intermediate between male ZZ and female ZW metabolic rate. For both species, our data indicate that differences in metabolism become more apparent as individuals become larger. Our findings provide some evidence for an energetic advantage from sex reversal in both species but do not exclude energetic processes as a constraint on the distribution of sex reversal in nature.
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Affiliation(s)
- Kristoffer H. Wild
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, AUS
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - John H. Roe
- Department of Biology, University of North Carolina Pembroke, Pembroke, NC 28372-1510, USA
| | - Lisa Schwanz
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Essie Rodgers
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Murdoch, WA 6150, Australia
| | - Duminda S. B. Dissanayake
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Arthur Georges
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Stephen D. Sarre
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, AUS
| | - Daniel W. A. Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, AUS
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Nemesházi E, Sramkó G, Laczkó L, Balogh E, Szatmári L, Vili N, Ujhegyi N, Üveges B, Bókony V. Novel genetic sex markers reveal unexpected lack of, and similar susceptibility to, sex reversal in free-living common toads in both natural and anthropogenic habitats. Mol Ecol 2022; 31:2032-2043. [PMID: 35146823 PMCID: PMC9544883 DOI: 10.1111/mec.16388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/27/2022] [Accepted: 02/04/2022] [Indexed: 11/29/2022]
Abstract
Anthropogenic environmental changes are affecting biodiversity and microevolution worldwide. Ectothermic vertebrates are especially vulnerable, since environmental changes can disrupt their sexual development and cause sex reversal, a mismatch between genetic and phenotypic sex. This can potentially lead to sex-ratio distortion and population decline. Despite these implications, we have scarce empirical knowledge on the incidence of sex reversal in nature. Populations in anthropogenic environments may be exposed to sex-reversing stimuli more frequently, which may lead to higher sex-reversal rate, or alternatively, these populations may adapt to resist sex reversal. We developed PCR-based genetic sex markers for the common toad (Bufo bufo) to assess the prevalence of sex reversal in wild populations living in natural, agricultural and urban habitats, and the susceptibility of the same populations to two ubiquitous estrogenic pollutants in a common-garden experiment. We found negligible sex-reversal frequency in free-living adults despite the presence of various endocrine-disrupting pollutants in their breeding ponds. Individuals from different habitat types showed similar susceptibility to sex reversal in the laboratory: all genetic males developed female phenotype when exposed to 1 µg/L 17α-ethinylestradiol (EE2) during larval development, whereas no sex reversal occurred in response to 1 ng/L EE2 and a glyphosate-based herbicide with 3 µg/L or 3 mg/L glyphosate. The latter results do not support that populations in anthropogenic habitats would have either increased propensity for or higher tolerance to chemically induced sex reversal. Thus, the extremely low sex-reversal frequency in wild toads compared to other ectothermic vertebrates studied before might indicate idiosyncratic, potentially species-specific resistance to sex reversal.
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Affiliation(s)
- Edina Nemesházi
- Conservation Genetics Research Group, Department of Ecology, University of Veterinary Medicine Budapest, István u. 2, 1078, Budapest, Hungary.,Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó u. 15, 1022, Budapest, Hungary
| | - Gábor Sramkó
- MTA-DE Lendület Evolutionary Phylogenomics Research Group, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Levente Laczkó
- MTA-DE Lendület Evolutionary Phylogenomics Research Group, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Emese Balogh
- Conservation Genetics Research Group, Department of Ecology, University of Veterinary Medicine Budapest, István u. 2, 1078, Budapest, Hungary
| | - Lajos Szatmári
- MTA-DE Lendület Evolutionary Phylogenomics Research Group, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Nóra Vili
- Conservation Genetics Research Group, Department of Ecology, University of Veterinary Medicine Budapest, István u. 2, 1078, Budapest, Hungary
| | - Nikolett Ujhegyi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó u. 15, 1022, Budapest, Hungary
| | - Bálint Üveges
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó u. 15, 1022, Budapest, Hungary.,Molecular Ecology and Evolution at Bangor, School of Natural Sciences, Bangor University, Bangor LL57 2UW, Wales, United Kingdom
| | - Veronika Bókony
- Conservation Genetics Research Group, Department of Ecology, University of Veterinary Medicine Budapest, István u. 2, 1078, Budapest, Hungary.,Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó u. 15, 1022, Budapest, Hungary
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