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Cornejo-Páramo P, Lira-Noriega A, Ramírez-Suástegui C, Méndez-de-la-Cruz FR, Székely T, Urrutia AO, Cortez D. Sex determination systems in reptiles are related to ambient temperature but not to the level of climatic fluctuation. BMC Evol Biol 2020; 20:103. [PMID: 32807071 PMCID: PMC7433102 DOI: 10.1186/s12862-020-01671-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 08/11/2020] [Indexed: 12/19/2022] Open
Abstract
Background Vertebrates exhibit diverse sex determination systems and reptiles stand out by having highly variable sex determinations that include temperature-dependent and genotypic sex determination (TSD and GSD, respectively). Theory predicts that populations living in either highly variable or cold climatic conditions should evolve genotypic sex determination to buffer the populations from extreme sex ratios, yet these fundamental predictions have not been tested across a wide range of taxa. Results Here, we use phylogenetic analyses of 213 reptile species representing 38 families (TSD = 101 species, GSD = 112 species) and climatic data to compare breeding environments between reptiles with GSD versus TSD. We show that GSD and TSD are confronted with the same level of climatic fluctuation during breeding seasons. However, TSD reptiles are significantly associated with warmer climates. We found a strong selection on the breeding season length that minimises exposure to cold and fluctuating climate. Phylogenetic path analyses comparing competing evolutionary hypotheses support that transitions in sex determination systems influenced the ambient temperature at which the species reproduces and nests. In turn, this interaction affects other variables such as the duration of the breeding season and life-history traits. Conclusions Taken together, our results challenge long-standing hypotheses about the association between sex determination and climate variability. We also show that ambient temperature is important during breeding seasons and it helps explain the effects of sex determination systems on the geographic distribution of extant reptile species.
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Affiliation(s)
- Paola Cornejo-Páramo
- Center for Genomics Sciences, UNAM, CP62210, Cuernavaca, Mexico.,Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Andrés Lira-Noriega
- CONACYT Research Fellow, Red de Estudios Moleculares Avanzados, Instituto de Ecología, A.C. Carretera antigua a Coatepec 351, Col. El Haya, Xalapa, Veracruz, Mexico
| | - Ciro Ramírez-Suástegui
- Center for Genomics Sciences, UNAM, CP62210, Cuernavaca, Mexico.,Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | | | - Tamás Székely
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.,Department of Evolutionary Zoology and Human Biology, University of Debrecen, Debrecen, H-4032, Hungary
| | - Araxi O Urrutia
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK. .,Institute of Ecology, UNAM, 04510, Mexico City, Mexico.
| | - Diego Cortez
- Center for Genomics Sciences, UNAM, CP62210, Cuernavaca, Mexico.
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Bozinovic F, Orellana MJ, Martel SI, Bogdanovich JM. Testing the heat-invariant and cold-variability tolerance hypotheses across geographic gradients. Comp Biochem Physiol A Mol Integr Physiol 2014; 178:46-50. [PMID: 25152532 DOI: 10.1016/j.cbpa.2014.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 11/23/2022]
Abstract
Changes in temperature across geographic gradients can occur on a wide temporal range, from fluctuations within hours as a result of day-night to those over many years. These events will drive many organisms towards their physiological limits of thermal tolerance. Recently, many reports support a limited scope for adaptive evolutionary responses to high temperatures, meaning a conserved heat tolerance among ectotherms in general. We address this problem and tested the heat and cold tolerance invariant-variant hypotheses in terrestrial isopods. We studied five different populations of Porcellio laevis and three populations of Porcellio scaber, spanning 30° S latitudinal gradient in Chile. The heat tolerance of woodlice was conserved with little variation along latitude and environmental temperatures, but cold tolerance decreases significantly with environmental temperatures and latitudes. Indeed, a significant and negative correlation was observed between cold tolerance and latitude. Also, significant and positive correlations were observed among cold tolerance and environmental temperatures. Conversely, heat tolerance was not significantly correlated with any of the environmental temperatures tested neither with latitude. This macrophysiological pattern indicated that heat and cold-tolerances of species and populations not always change across geographical gradients meaning that thermal tolerance responses to high temperatures may be evolutionary constrained.
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