Causes and Consequences of Evolutionary Transitions in the Level of Phenotypic Plasticity of Reptilian Sex Determination

2018 ◽  
pp. 345-363
Author(s):  
Nicole Valenzuela
Keyword(s):  
Phenotypic Plasticity ◽  
Sex Determination ◽  
Evolutionary Transitions

scholarly journals Are evolutionary transitions in sexual size dimorphism related to sex determination in reptiles?

2021 ◽  
Vol 34 (4) ◽  
pp. 594-603
Author(s):  
Gergely Katona ◽  
Balázs Vági ◽  
Zsolt Végvári ◽  
András Liker ◽  
Robert P. Freckleton ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sexual Size Dimorphism ◽  
Evolutionary Transitions ◽  
Size Dimorphism

scholarly journals Evolutionary transitions between mechanisms of sex determination in vertebrates

2011 ◽  
Vol 7 (3) ◽  
pp. 443-448 ◽  
Author(s):  
Alexander E. Quinn ◽  
Stephen D. Sarre ◽  
Tariq Ezaz ◽  
Jennifer A. Marshall Graves ◽  
Arthur Georges
Keyword(s):  
Sex Determination ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Molecular Pathways ◽  
Genetic Contribution ◽  
Temperature Dependent ◽  
Trait Evolution ◽  
Evolutionary Transitions ◽  
Dichotomous Outcome ◽  
Threshold Trait

Sex in many organisms is a dichotomous phenotype—individuals are either male or female. The molecular pathways underlying sex determination are governed by the genetic contribution of parents to the zygote, the environment in which the zygote develops or interaction of the two, depending on the species. Systems in which multiple interacting influences or a continuously varying influence (such as temperature) determines a dichotomous outcome have at least one threshold. We show that when sex is viewed as a threshold trait, evolution in that threshold can permit novel transitions between genotypic and temperature-dependent sex determination (TSD) and remarkably, between male (XX/XY) and female (ZZ/ZW) heterogamety. Transitions are possible without substantive genotypic innovation of novel sex-determining mutations or transpositions, so that the master sex gene and sex chromosome pair can be retained in ZW–XY transitions. We also show that evolution in the threshold can explain all observed patterns in vertebrate TSD, when coupled with evolution in embryonic survivorship limits.

scholarly journals Flagellar phenotypic plasticity in volvocalean algae correlates with Péclet number

2011 ◽  
Vol 8 (63) ◽  
pp. 1409-1417 ◽  
Author(s):  
Cristian A. Solari ◽  
Knut Drescher ◽  
Sujoy Ganguly ◽  
John O. Kessler ◽  
Richard E. Michod ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Nutrient Uptake ◽  
Peclet Number ◽  
Large Species ◽  
Volvox Carteri ◽  
Evolutionary Transitions ◽  
Péclet Number ◽  
Flow Speeds ◽  
Propulsion Force ◽  
Opposing Effects

Flagella-generated fluid stirring has been suggested to enhance nutrient uptake for sufficiently large micro-organisms, and to have played a role in evolutionary transitions to multicellularity. A corollary to this predicted size-dependent benefit is a propensity for phenotypic plasticity in the flow-generating mechanism to appear in large species under nutrient deprivation. We examined four species of volvocalean algae whose radii and flow speeds differ greatly, with Péclet numbers ( Pe ) separated by several orders of magnitude. Populations of unicellular Chlamydomonas reinhardtii and one- to eight-celled Gonium pectorale ( Pe ∼ 0.1–1) and multicellular Volvox carteri and Volvox barberi ( Pe ∼ 100) were grown in diluted and undiluted media. For C. reinhardtii and G. pectorale , decreasing the nutrient concentration resulted in smaller cells, but had no effect on flagellar length and propulsion force. In contrast, these conditions induced Volvox colonies to grow larger and increase their flagellar length, separating the somatic cells further. Detailed studies on V. carteri found that the opposing effects of increasing beating force and flagellar spacing balance, so the fluid speed across the colony surface remains unchanged between nutrient conditions. These results lend further support to the hypothesized link between the Péclet number, nutrient uptake and the evolution of biological complexity in the Volvocales.

scholarly journals Conservation of sex-linked markers among conspecific populations of a viviparous skink, Niveoscincus ocellatus, exhibiting genetic and temperature dependent sex determination

2018 ◽  
Author(s):  
Peta Hill ◽  
Christopher P. Burridge ◽  
Tariq Ezaz ◽  
Erik Wapstra
Keyword(s):  
Linkage Disequilibrium ◽  
Sex Ratio ◽  
Sex Determination ◽  
Temperature Dependent ◽  
Offspring Sex Ratio ◽  
Evolutionary Transitions ◽  
Offspring Sex ◽  
Determination System ◽  
Sex Determination System ◽  
Male Heterogamety

AbstractSex determination systems are exceptionally diverse and have undergone multiple and independent evolutionary transitions among species, particularly reptiles. However, the mechanisms underlying these transitions have not been established. Here we tested for differences in sex-linked markers in the only known reptile that is polymorphic for sex determination system, the spotted snow skink, Niveoscincus ocellatus, to quantify the genomic differences that have accompanied this transition. In a highland population, sex is determined genetically, whilst in a lowland population, offspring sex ratio is influenced by temperature. We found a similar number of sex-linked loci in each population, including shared loci, with genotypes consistent with male heterogamety (XY). However, population-specific linkage disequilibrium suggests greater divergence of sex chromosomes in the highland population. Our results suggest that transitions between sex determination systems (GSD and TSD-like systems) can be facilitated by subtle genetic differences.

scholarly journals Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome

2016 ◽  
Vol 113 (52) ◽  
pp. 15036-15041 ◽  
Author(s):  
Sébastien Leclercq ◽  
Julien Thézé ◽  
Mohamed Amine Chebbi ◽  
Isabelle Giraud ◽  
Bouziane Moumen ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Nuclear Genome ◽  
Closely Related Species ◽  
Evolutionary Transitions ◽  
Female Sex ◽  
Bacterial Endosymbionts ◽  
The Common ◽  
And Behavior

Sex determination is a fundamental developmental pathway governing male and female differentiation, with profound implications for morphology, reproductive strategies, and behavior. In animals, sex differences between males and females are generally determined by genetic factors carried by sex chromosomes. Sex chromosomes are remarkably variable in origin and can differ even between closely related species, indicating that transitions occur frequently and independently in different groups of organisms. The evolutionary causes underlying sex chromosome turnover are poorly understood, however. Here we provide evidence indicating that Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare. We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. The Wolbachia insert shows perfect linkage to the female sex, occurs in a male genetic background (i.e., lacking the ancestral W female sex chromosome), and is hemizygous. Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs, and that the chromosome carrying the insert is a new W sex chromosome. Thus, bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes. We conclude that sex ratio distorters, such as Wolbachia endosymbionts, can be powerful agents of evolutionary transitions in sex determination systems in animals.

scholarly journals Genome-Wide SNP Analysis of Male and Female Rice Field Frogs, Hoplobatrachus rugulosus, Supports a Non-Genetic Sex Determination System

Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 501
Author(s):  
Thitipong Panthum ◽  
Worapong Singchat ◽  
Nararat Laopichienpong ◽  
Syed Farhan Ahmad ◽  
Ekaphan Kraichak ◽  
...  
Keyword(s):  
Sex Determination ◽  
Rice Field ◽  
Sex Chromosome ◽  
The Body ◽  
Threshold Temperature ◽  
Snp Analysis ◽  
Amphibian Species ◽  
Evolutionary Transitions ◽  
Evolutionary Trap ◽  
Sex Determination System

Sex determination systems (SDSs) in anurans are diverse and have undergone independent evolutionary transitions among species. The mode of sexual reproduction of the rice field frog (Hoplobatrachus rugulosus)—an economically viable, edible amphibian species—is not well known. Previous studies have proposed that threshold temperature conditions may determine sex in these frogs. To elucidate the SDS in H. rugulosus, we karyotyped 10 male and 12 female frogs, and performed fluorescence in situ hybridization combined with sequencing analyses using DArTseq™. Our results revealed a highly conserved karyotype with no sex chromosome heteromorphism, and the sequencing analyses did not identify any consistent sex-linked loci, supporting the hypothesis of temperature-dependent sex determination. The results of this study, and others, on SDSs in the rice field frog and related species also provide support for the theory that heteromorphic sex chromosomes may lead to an evolutionary trap that prevents variable SDSs. These findings add important information to the body of knowledge on H. rugulosus and are likely to have a significant impact on the productivity and economic success of rice field frog farming.

scholarly journals Differences in Homomorphic Sex Chromosomes Are Associated with Population Divergence in Sex Determination in Carinascincus ocellatus (Scincidae: Lygosominae)

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 291
Author(s):  
Peta Hill ◽  
Foyez Shams ◽  
Christopher P. Burridge ◽  
Erik Wapstra ◽  
Tariq Ezaz
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Population Divergence ◽  
Sex Chromosome Evolution ◽  
Evolutionary Transitions ◽  
Evolutionary Origins ◽  
Probe Set

Sex determination directs development as male or female in sexually reproducing organisms. Evolutionary transitions in sex determination have occurred frequently, suggesting simple mechanisms behind the transitions, yet their detail remains elusive. Here we explore the links between mechanisms of transitions in sex determination and sex chromosome evolution at both recent and deeper temporal scales (<1 Myr; ~79 Myr). We studied a rare example of a species with intraspecific variation in sex determination, Carinascincus ocellatus, and a relative, Liopholis whitii, using c-banding and mapping of repeat motifs and a custom Y chromosome probe set to identify the sex chromosomes. We identified both unique and conserved regions of the Y chromosome among C. ocellatus populations differing in sex determination. There was no evidence for homology of sex chromosomes between C. ocellatus and L. whitii, suggesting independent evolutionary origins. We discuss sex chromosome homology between members of the subfamily Lygosominae and propose links between sex chromosome evolution, sex determination transitions, and karyotype evolution.

scholarly journals Parental energy-sensing pathways control intergenerational offspring sex determination in the nematode Auanema freiburgensis

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Pedro Robles ◽  
Anisa Turner ◽  
Giusy Zuco ◽  
Sally Adams ◽  
Panagiota Paganopolou ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Sex Determination ◽  
Nutrient Sensing ◽  
Transgenerational Inheritance ◽  
Acetylation Status ◽  
Mechanistic Target Of Rapamycin ◽  
Offspring Sex ◽  
Energy Sensing ◽  
Amp Activated Protein Kinase ◽  
Chromatin Acetylation

Abstract Background Environmental stimuli experienced by the parental generation influence the phenotype of subsequent generations (Demoinet et al., Proc Natl Acad Sci U S A 114:E2689-E2698, 2017; Burton et al., Nat Cell Biol 19:252–257, 2017; Agrawal et al., Nature 401:60-63, 1999). The effects of these stimuli on the parental generation may be passed through the germline, but the mechanisms at the basis of this non-Mendelian type of inheritance, their level of conservation, how they lead to adaptive vs non-adaptive, and intergenerational vs transgenerational inheritance are poorly understood. Here we show that modulation of nutrient-sensing pathways in the parental generation of the nematode Auanema freiburgensis regulates phenotypic plasticity of its offspring. Results In response to con-specific pheromones indicative of stress, AMP-activated protein kinase (AMPK), mechanistic target of rapamycin complex 1 (mTORC1), and insulin signaling regulate stress resistance and sex determination across one generation, and these effects can be mimicked by pathway modulators. The effectors of these pathways are closely associated with the chromatin, and their regulation affects the chromatin acetylation status in the germline. Conclusion These results suggest that highly conserved metabolic sensors regulate phenotypic plasticity through regulation of subcellular localization of their effectors, leading to changes in chromatin acetylation and epigenetic status of the germline.

scholarly journals Environmental stress maintains trioecy in nematode worms

2019 ◽  
Author(s):  
Ashlyn G. Anderson ◽  
Louis T. Bubrig ◽  
Janna L. Fierst
Keyword(s):  
Life History ◽  
Sex Determination ◽  
Environmental Conditions ◽  
Natural Habitat ◽  
Population Level ◽  
Evolutionary Transitions ◽  
Sexual Systems ◽  
Determination System ◽  
Stable Maintenance ◽  
Sex Determination System

AbstractSex is determined by chromosomes in mammals but it can be influenced by the environment in many worms, crustaceans and vertebrates. Despite this, there is little understanding of the relationship between ecology and the evolution of sexual systems. The nematode Auanema freiburgensis has a unique sex determination system in which individuals carrying one X chromosome develop into males while XX individuals develop into females in stress-free environments and self-fertile hermaphrodites in stressful environments. Theory predicts that trioecious populations with coexisting males, females and hermaphrodites should be unstable intermediates in evolutionary transitions between mating systems. In this article we study a mathematical model of reproductive evolution based on the unique life history and sex determination of A. freiburgensis. We develop the model in two scenarios, one where the relative production of hermaphrodites and females is entirely dependent on the environment and one based on empirical measurements of a population that displays incomplete, ‘leaky’ environmental dependence. In the first scenario environmental conditions can push the population along an evolutionary continuum and result in the stable maintenance of multiple reproductive systems. The second ‘leaky’ scenario results in the maintenance of three sexes for all environmental conditions. Theoretical investigations of reproductive system transitions have focused on the evolutionary costs and benefits of sex. Here, we show that the flexible sex determination system of A. freiburgensis may contribute to population-level resilience in the microscopic nematode’s patchy, ephemeral natural habitat. Our results demonstrate that life history, ecology and environment may play defining roles in the evolution of sexual systems.

scholarly journals Sexual Development and the Environment: Conclusions from 40 Years of Theory

2021 ◽  
pp. 1-16
Author(s):  
Lisa E. Schwanz ◽  
Arthur Georges
Keyword(s):  
Sex Determination ◽  
Local Adaptation ◽  
Temperature Sensitivity ◽  
Sexual Development ◽  
Evolutionary Dynamics ◽  
Sex Ratios ◽  
Network Models ◽  
Theoretical Models ◽  
Evolutionary Transitions ◽  
Genotypic Sex Determination

In this review, we consider the insight that has been gained through theoretical examination of environmental sex determination (ESD) and thermolability – how theory has progressed our understanding of the ecological and evolutionary dynamics associated with ESD, the transitional pathways between different modes of sex determination, and the underlying mechanisms. Following decades of theory on the adaptive benefits of ESD, several hypotheses seem promising. These hypotheses focus on the importance of <i>differential fitness</i> (sex-specific effects of temperature on fitness) in generating selection for ESD, but highlight alternative ways differential fitness arises: seasonal impacts on growth, sex-specific ages of maturation, and sex-biased dispersal. ESD has the potential to generate biased sex ratios quite easily, leading to complex feedbacks between the ecology and evolution of ESD. Frequency-dependent selection on sex acts on ESD-related traits, driving local adaptation or plasticity to restore equilibrium sex ratio. However, migration and overlapping generations (“mixing”) diminish local adaptation and leave each cohort/population with the potential for biased sex ratios. Incorporating mechanism into ecology and evolution models reveals similarities between different sex-determining systems. Dosage and gene regulatory network models of sexual development are beginning to shed light on how temperature sensitivity and thresholds may arise. The unavoidable temperature sensitivity in sex-determining systems inherent to these models suggests that evolutionary transitions between genotypic sex determination (GSD) and temperature-dependent sex determination, and between different forms of GSD, are simple and elegant. Theoretical models are often best-served by considering a single piece of a puzzle; however, there is much to gain from reflecting on all of the pieces together in one integrative picture.

Sign in / Sign up

Export Citation Format

Share Document