Embryonic Temperature Programs Phenotype in Reptiles

Singh, Sunil Kumar; Das, Debojyoti; Rhen, Turk

doi:10.3389/fphys.2020.00035

Cited by 44 publications

(38 citation statements)

References 148 publications

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“…Whether examined at macro‐ or microgeographic scales, physiological variation among populations may reflect any combination of evolutionary divergence and phenotypic plasticity (Newman, 1992; Noble et al, 2018; Singh et al, 2020). Importantly, we distinguish here between active plasticity and a passive response to temperaturedriven by changes in biochemical rates (Havird et al, 2020).…”

Section: Evolution and Plasticitymentioning

confidence: 99%

“…Though further tests are needed to understand the interaction of plasticity and evolution in the thermal traits of reptiles and amphibians, plasticity in response to the thermal environments of early development could lead to population‐level adaptation over time (Noble et al, 2019). In reptiles, developmental plasticity for preferred or selected body temperatures has been observed in about half the studies that have tested for it, mostly by incubating eggs across a range of temperatures and measuring phenotypic traits at later (usually neonate) life‐history stages (e.g., S. J. Arnold et al, 1995; Aubret & Shine, 2010; Blouin‐Demers et al, 2000; Blumberget al, 2002; Esquerré et al, 2014; O'Steen, 1998; reviewed in Refsnider et al, 2019; Singh et al, 2020; Tamplin & Cyr, 2011). Unlike thermal preference, CT max in reptiles appears to be little affected by developmental temperature (Abayarathna et al, 2019; Gunderson et al, 2020; Llewyn et al, 2018) though there may be more of an effect on CT min (Dayananda et al, 2017; Du et al, 2010).…”

Section: Evolution and Plasticitymentioning

confidence: 99%

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Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

et al. 2020

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Ectothermic animals, such as amphibians and reptiles, are particularly sensitive to rapidly warming global temperatures. One response in these organisms may be to evolve aspects of their thermal physiology. If this response is adaptive and can occur on the appropriate time scale, it may facilitate population or species persistence in the changed environments. However, thermal physiological traits have classically been thought to evolve too slowly to keep pace with environmental change in longer‐lived vertebrates. Even as empirical work of the mid‐20th century offers mixed support for conservatism in thermal physiological traits, the generalization of low evolutionary potential in thermal traits is commonly invoked. Here, we revisit this hypothesis to better understand the mechanisms guiding the timing and patterns of physiological evolution. Characterizing the potential interactions among evolution, plasticity, behavior, and ontogenetic shifts in thermal physiology is critical for accurate prediction of how organisms will respond to our rapidly warming world. Recent work provides evidence that thermal physiological traits are not as evolutionarily rigid as once believed, with many examples of divergence in several aspects of thermal physiology at multiple phylogenetic scales. However, slow rates of evolution are often still observed, particularly at the warm end of the thermal performance curve. Furthermore, the context‐specificity of many responses makes broad generalizations about the potential evolvability of traits tenuous. We outline potential factors and considerations that require closer scrutiny to understand and predict reptile and amphibian evolutionary responses to climate change, particularly regarding the underlying genetic architecture facilitating or limiting thermal evolution.

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Section: Evolution and Plasticitymentioning

confidence: 99%

Section: Evolution and Plasticitymentioning

confidence: 99%

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

et al. 2020

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“…In ectothermic animals, incubation temperatures during embryonic development affect different traits such as body size and shape, locomotor performance, and sexual phenotype, among others [127,128]. Exposure to high temperatures can result in neural tube defects and craniofacial malformations, plus defects in limbs and vertebrae [129][130][131].…”

Section: Discussionmentioning

confidence: 99%

“…In freshwater turtles, malformations were observed in the tail and carapace [132]. As in mammals, early developmental stages in reptiles are more susceptible to the teratogenic effects of high temperatures [128,131,132]. In sea turtles, hyperthermia and low humidity during embryonic development may cause low hatching success, high mortality and femalebiased sex ratios [133][134][135][136], as well as craniofacial, limb, and pigmentation disorders [21].…”

Section: Discussionmentioning

confidence: 99%

Congenital Malformations in Sea Turtles: Puzzling Interplay between Genes and Environment

Martín-del-Campo

Calderón-Campuzano²,

Rojas‐Lleonart

et al. 2021

Animals

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The completion of embryonic development depends, in part, on the interplay between genetic factors and environmental conditions, and any alteration during development may affect embryonic genetic and epigenetic regulatory pathways leading to congenital malformations, which are mostly incompatible with life. Oviparous reptiles, such as sea turtles, that produce numerous eggs in a clutch that is buried on the beach provide an opportunity to study embryonic mortality associated with malformations that occur at different times during development, or that prevent the hatchling from emerging from the nest. In sea turtles, the presence of congenital malformations frequently leads to mortality. A few years ago, a detailed study was performed on external congenital malformations in three species of sea turtles from the Mexican Pacific and Caribbean coasts, the hawksbill turtle, Eretmochelys imbricata (n = 23,559 eggs), the green turtle, Chelonia mydas (n = 17,690 eggs), and the olive ridley, Lepidochelys olivacea (n = 20,257 eggs), finding 63 types of congenital malformations, of which 38 were new reports. Of the three species, the olive ridley showed a higher incidence of severe anomalies in the craniofacial region (49%), indicating alterations of early developmental pathways; however, several malformations were also observed in the body, including defects in the carapace (45%) and limbs (33%), as well as pigmentation disorders (20%), indicating that deviations occurred during the middle and later stages of development. Although intrinsic factors (i.e., genetic mutations or epigenetic modifications) are difficult to monitor in the field, some environmental factors (such as the incubation temperature, humidity, and probably the status of feeding areas) are, to some extent, less difficult to monitor and/or control. In this review, we describe the aetiology of different malformations observed in sea turtle embryos, and provide some actions that can reduce embryonic mortality.

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“…Phylogenetic analyses indicate that TSD is the ancestral mode of sex determination and that genotypic sex determination evolved independently several times ( Janzen and Krenz 2004 , Valenzuela and Adams 2011 , Pokorná and Kratochvil 2016 ). In addition to its effect on the gonads, incubation temperature has a significant impact on growth, physiology, and behavior in turtles and other reptiles ( Rhen and Lang 2004 , Noble et al 2018 , While et al 2018 , Singh et al 2020 ).…”

mentioning

confidence: 99%

Draft Genome of the Common Snapping Turtle,Chelydra serpentina, a Model for Phenotypic Plasticity in Reptiles

Das

Singh

Bierstedt

et al. 2020

G3 Genes|Genomes|Genetics

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Turtles are iconic reptiles that inhabit a range of ecosystems from oceans to deserts and climates from the tropics to northern temperate regions. Yet, we have little understanding of the genetic adaptations that allow turtles to survive and reproduce in such diverse environments. Common snapping turtles, Chelydra serpentina, are an ideal model species for studying adaptation to climate because they are widely distributed from tropical to northern temperate zones in North America. They are also easy to maintain and breed in captivity and produce large clutch sizes, which makes them amenable to quantitative genetic and molecular genetic studies of traits like temperature-dependent sex determination. We therefore established a captive breeding colony and sequenced DNA from one female using both short and long reads. After trimming and filtering, we had 209.51Gb of Illumina reads, 25.72Gb of PacBio reads, and 21.72 Gb of Nanopore reads. The assembled genome was 2.258 Gb in size and had 13,224 scaffolds with an N50 of 5.59Mb. The longest scaffold was 27.24Mb. BUSCO analysis revealed 97.4% of core vertebrate genes in the genome. We identified 3.27 million SNPs in the reference turtle, which indicates a relatively high level of individual heterozygosity. We assembled the transcriptome using RNA-Seq data and used gene prediction software to produce 22,812 models of protein coding genes. The quality and contiguity of the snapping turtle genome is similar to or better than most published reptile genomes. The genome and genetic variants identified here provide a foundation for future studies of adaptation to climate.

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Embryonic Temperature Programs Phenotype in Reptiles

Cited by 44 publications

References 148 publications

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

Congenital Malformations in Sea Turtles: Puzzling Interplay between Genes and Environment

Draft Genome of the Common Snapping Turtle,Chelydra serpentina, a Model for Phenotypic Plasticity in Reptiles

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