scholarly journals Baby fish working out: an epigenetic source of adaptive variation in the cichlid jaw

2017 ◽  
Vol 284 (1860) ◽  
pp. 20171018 ◽  
Author(s):  
Yinan Hu ◽  
R. Craig Albertson
Keyword(s):  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Mechanical Load ◽  
Skeletal Development ◽  
Experimental Manipulation ◽  
Adaptive Variation ◽  
Skeletal Morphology ◽  
Trophic Morphology ◽  
Evo Devo ◽  
Working Out

Understanding the developmental processes that underlie the production of adaptive variation (i.e. the ‘arrival of the fittest’) is a major goal of evolutionary biology. While most evo-devo studies focus on the genetic underpinnings of adaptive phenotypic variation, factors beyond changes in nucleotide sequence can also play a major role in shaping developmental outcomes. Here, we document a vigorous but enigmatic gaping behaviour during the early development of Lake Malawi cichlid larvae. The onset of the behaviour precedes the formation of bone, and we predicted that it might influence craniofacial shape by affecting the mechanical environment in which bone develops. Consistent with this, we found that both natural variation and experimental manipulation of this behaviour induced differential skeletal development that foreshadows adaptive variation in adult trophic morphology. In fact, the magnitude of difference in skeletal morphology induced by these simple shifts in behaviour was similar to those predicted to be caused by genetic factors. Finally, we demonstrate that this mechanical-load-induced shift in skeletal development is associated with differences in ptch1 expression, a gene previously implicated in mediating between-species differences in skeletal shape. Our results underscore the complexity of development, and the importance of epigenetic ( sensu Waddington) mechanisms in determining adaptive phenotypic variation.

Deconstructing and reconstructing joint hypermobility on an evo-devo perspective

Rheumatology ◽  
2021 ◽  
Author(s):  
Marco Castori
Keyword(s):  
Evolutionary Biology ◽  
Phenotypic Variability ◽  
Morphological Variability ◽  
Complex Trait ◽  
Joint Hypermobility ◽  
Integration Model ◽  
Ehlers Danlos Syndrome ◽  
Evo Devo ◽  
Derivatives Of ◽  
Continuous Traits

Abstract Joint hypermobility is a common characteristic in humans. Its non-casual association with various musculoskeletal complaints is known and currently defined “the spectrum”. It includes hypermobile Ehlers–Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD). hEDS is recognized by a set of descriptive criteria, while HSD is the background diagnosis for individuals not fulfilling these criteria. Little is known about the aetiopathogenesis of the spectrum. It may be interpreted as a complex trait according to the integration model. Particularly, the spectrum is common in the general population, affects morphology, presents extreme clinical variability and is characterized by marked sex bias without a clear Mendelian or hormonal explanation. Joint hypermobility and the other hEDS systemic criteria are intended as qualitative derivatives of continuous traits of normal morphological variability. The need for a minimum set of criteria for hEDS diagnosis implies a tendency to co-vary of these underlying continuous traits. In evolutionary biology, such a co-variation (i.e. integration) is driven by multiple forces, including genetic, developmental, functional and environmental/acquired interactors. The aetiopathogenesis of the spectrum may be resolved by a deeper understanding of phenotypic variability, which superimposes on normal morphological variability.

scholarly journals A simple index to quantify and compare the magnitude of intraspecific geographic plumage colour variation in typical antbirds (Aves: Passeriformes: Thamnophilidae)

2020 ◽  
Vol 130 (2) ◽  
pp. 239-246
Author(s):  
Rafael S Marcondes ◽  
Robb T Brumfield
Keyword(s):  
Geographic Variation ◽  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Phylogeographic Structure ◽  
Plumage Colour ◽  
Colour Space ◽  
Colour Variation ◽  
Simple Index ◽  
High Prevalence ◽  
Variable Species

Abstract Intraspecific geographic phenotypic variation is a crucial theme in evolutionary biology. Comparing its magnitude across species can provide insights into its ecological and genetic correlates. Here, we developed an index, which we dub the V index, to quantify intraspecific plumage colour variation in typical antbirds (Thamnophilidae), a family which has long interested ornithologists due to a high prevalence of intraspecific variation. The V index is based on a bivariate colour space defined by brightness and redness. Its value for each species equals the mean area occupied by each of its subspecies in that colour space, divided by the area of the species. Lower values indicate greater intraspecific geographic variation. Based on this index, Thamnophilus caerulescens (Variable Antshrike) was exceptionally geographically variable compared to other thamnophilids, as previously suggested based on qualitative evidence. In general, we found that the most variable species had disjunct distributions and deep phylogeographic structure, suggesting an effect of historical population dynamics in producing geographic variation. The V index can be adapted for use with other taxa, traits, and taxonomic levels, and we expect it will instigate novel ways of thinking about phenotypic variation in birds and other animals.

Evolution Makes More Sense in the Light of Development

2014 ◽  
Vol 76 (8) ◽  
pp. 493-498 ◽  
Author(s):  
Kostas Kampourakis ◽  
Alessandro Minelli
Keyword(s):  
Developmental Biology ◽  
Evolutionary Biology ◽  
Conceptual Development ◽  
Evolutionary Developmental Biology ◽  
Public Communication ◽  
Common Ancestry ◽  
Development Research ◽  
The Public ◽  
Psychological Essentialism ◽  
Evo Devo

We highlight some important conceptual issues that biologists should take into account when teaching evolutionary biology or communicating it to the public. We first present conclusions from conceptual development research on how particular human intuitions, namely design teleology and psychological essentialism, influence the understanding of evolution. We argue that these two intuitions form important conceptual obstacles to understanding evolution that should be explicitly addressed during instruction and public communication. Given that a major issue in evolution is understanding how very different forms may share common ancestry – antievolutionists have argued that this is inconceivable – we suggest that evolutionary developmental biology (evo-devo), which provides concepts and evidence that large morphological change is possible, could be used to address the intuitions that organisms have fixed essences (psychological essentialism) and that their structure indicates some kind of intentional design (design teleology).

scholarly journals Searching for principles of microbial physiology

2020 ◽  
Vol 44 (6) ◽  
pp. 821-844
Author(s):  
Frank J Bruggeman ◽  
Robert Planqué ◽  
Douwe Molenaar ◽  
Bas Teusink
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Evolutionary Biology ◽  
Current Status ◽  
Basic Principles ◽  
Future Directions ◽  
Selective Pressures ◽  
State Growth ◽  
Microbial Systems ◽  
Working Out

ABSTRACT Why do evolutionarily distinct microorganisms display similar physiological behaviours? Why are transitions from high-ATP yield to low(er)-ATP yield metabolisms so widespread across species? Why is fast growth generally accompanied with low stress tolerance? Do these regularities occur because most microbial species are subject to the same selective pressures and physicochemical constraints? If so, a broadly-applicable theory might be developed that predicts common microbiological behaviours. Microbial systems biologists have been working out the contours of this theory for the last two decades, guided by experimental data. At its foundations lie basic principles from evolutionary biology, enzyme biochemistry, metabolism, cell composition and steady-state growth. The theory makes predictions about fitness costs and benefits of protein expression, physicochemical constraints on cell growth and characteristics of optimal metabolisms that maximise growth rate. Comparisons of the theory with experimental data indicates that microorganisms often aim for maximisation of growth rate, also in the presence of stresses; they often express optimal metabolisms and metabolic proteins at optimal concentrations. This review explains the current status of the theory for microbiologists; its roots, predictions, experimental evidence and future directions.

scholarly journals Differential effects of steroid hormones on levels of genetic variance in a wild bird: possible mechanism of maternal-effects x genetic variance interaction?

2020 ◽  
Author(s):  
Szymon Marian Drobniak ◽  
Joanna Sudyka ◽  
Mariusz Cichoń ◽  
Aneta Arct ◽  
Lars Gustafsson ◽  
...  
Keyword(s):  
Steroid Hormones ◽  
Maternal Effects ◽  
Evolutionary Biology ◽  
Quantitative Traits ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Experimental Manipulation ◽  
Evolutionary Potential ◽  
Blue Tits ◽  
Rearing Effects

Genetic variation is one of the key concepts in evolutionary biology and an important prerequisite of evolutionary change. Still, we know very little about processes that modulate its levels in wild populations. In particular – we still are to understand why genetic variances often depend on environmental conditions. One of possible environment-sensitive modulators of observed levels of genetic variance are maternal effects. In this study we attempt to experimentally test the hypothesis that maternally-transmitted agents (e.g. hormones) may influence the expression of genetic variance in quantitative traits in the offspring. We manipulated the levels of steroid hormones (testosterone and corticosterone) in eggs laid by blue tits in a wild population. Our experimental setup allowed for full crossing of genetic and rearing effects with the experimental manipulation. We observed, that birds treated with corticosterone exhibited a significant decrease in genetic variance of tarsus length. We also observed less pronounced, marginally significant effects of hormonal administration on the patterns of genetic correlations between traits expressed under varying pre-hatching hormonal conditions. Our study indicates, that maternally transmitted substances such as hormones may have measurable impact on the levels of genetic variance – and hence, on the evolutionary potential of quantitative traits.

scholarly journals On the Use of Blood Samples for Measuring DNA Methylation in Ecological Epigenetic Studies

2020 ◽  
Vol 60 (6) ◽  
pp. 1558-1566 ◽  
Author(s):  
Arild Husby
Keyword(s):  
Dna Methylation ◽  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Phenotypic Diversity ◽  
Genomic Region ◽  
Epigenetic Mechanism ◽  
Blood Samples ◽  
Reduced Representation ◽  
Bisulfite Treatment ◽  
Methylation Patterns

Synopsis There is increasing interest in understanding the potential for epigenetic factors to contribute to phenotypic diversity in evolutionary biology. One well studied epigenetic mechanism is DNA methylation, the addition of a methyl group to cytosines, which have the potential to alter gene expression depending on the genomic region in which it takes place. Obtaining information about DNA methylation at genome-wide scale has become straightforward with the use of bisulfite treatment in combination with reduced representation or whole-genome sequencing. While it is well recognized that methylation is tissue specific, a frequent limitation for many studies is that sampling-specific tissues may require sacrificing individuals, something which is generally undesirable and sometimes impossible. Instead, information about DNA methylation patterns in the blood is frequently used as a proxy tissue. This can obviously be problematic if methylation patterns in the blood do not reflect that in the relevant tissue. Understanding how, or if, DNA methylation in blood reflect DNA methylation patterns in other tissues is therefore of utmost importance if we are to make inferences about how observed differences in methylation or temporal changes in methylation can contribute to phenotypic variation. The aim of this review is to examine what we know about the potential for using blood samples in ecological epigenetic studies. I briefly outline some methods by which we can measure DNA methylation before I examine studies that have compared DNA methylation patterns across different tissues and, finally, examine how useful blood samples may be for ecological studies of DNA methylation. Ecological epigenetic studies are in their infancy, but it is paramount for the field to move forward to have detailed information about tissue and time dependence relationships in methylation to gain insights into if blood DNA methylation patterns can be a reliable bioindicator for changes in methylation that generate phenotypic variation in ecologically important traits.

scholarly journals The Dual Role of Evo-Devo Mechanisms and the Extended Evolutionary Synthesis

2019 ◽  
Vol 22 (2) ◽  
pp. 251-275
Author(s):  
Guillermo Folguera ◽  
Nicolás Lavagnino
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary Developmental Biology ◽  
Biological Variation ◽  
Dual Role ◽  
Evolutionary Synthesis ◽  
Main Question ◽  
Extended Evolutionary Synthesis ◽  
Evo Devo ◽  
Somatic Selection

The distinction between mechanisms that generate biological variation and mechanisms that modify it has been important in contemporary Biology, especially since the establishment of the Evolutionary Synthesis (ES) in the first part of the twentieth century. In the ES, and in its subsequent legacy to evolutionary biology, the focus was directed at mechanisms that modify biological variation. In recent years, evo-devo (Evolutionary Developmental Biology) emerged as an area of knowledge that proposes to extend the ES in many forms. In this sense, given that evo-devo integrates different areas of Biology, different types of mechanisms can be found. In order to understand evo-devo mechanisms, as well as its relation with the ES, we analyzed the role that evo-devo mechanisms play with respect to biological variation. The main question in our analysis was: do evo-devo mechanisms have a function of generators and/or modifiers of biological variation? We focused on three evo-devo mechanisms: environmental induction, hypervariability/somatic selection and developmental bias. Our analysis showed a different characterization of the action of evo-devo mechanisms. This heterogeneity in the role of evo-devo mechanisms shows that, in general, the distinction is maintained but there is a mechanism that presents a dual role. Our analysis indicates that, at least with respect to mechanisms, evo-devo extends and departs from what was proposed in the evolutionary synthesis.

Beyond beanbag semantics

2003 ◽  
Vol 26 (6) ◽  
pp. 673-674
Author(s):  
Daniel C. Dennett
Keyword(s):  
Evolutionary Biology ◽  
Evo Devo

Jackendoff's “mentalistic” semantics looks more radical than it is. It can best be understood as a necessary corrective to the traditional oversimplification that holds that psychological variation “cancels out” on the path from word to world. This reform parallels the “evo-devo” reform in evolutionary biology.

scholarly journals Evolution and development: some insights from evolutionary theory

2001 ◽  
Vol 73 (3) ◽  
pp. 385-395 ◽  
Author(s):  
JEAN R. DAVID
Keyword(s):  
Evolutionary Theory ◽  
Evolutionary Biology ◽  
Evolutionary Genetics ◽  
Developmental Genetics ◽  
Homologous Genes ◽  
Evolution And Development ◽  
Evo Devo ◽  
Why Questions ◽  
The 19Th Century ◽  
Novel Structures

Developmental biology and evolutionary biology are both mature integrative disciplines which started in the 19th century and then followed parallel and independent scientific pathways. Recently, a genetical component has stepped into both disciplines (developmental genetics and evolutionary genetics) pointing out the need for future convergent maturation. Indeed, the Evo-Devo approach is becoming popular among developmental biologists, based on the facts that distant groups share a common ancestry, that precise phylogenies can be worked out and that homologous genes often play similar roles during the development of very different organisms. In this essay, I try to show that the real future of Evo-Devo thinking is still broader. The evolutionary theory is a set of diverse concepts which can and should be used in any biological field. Evolutionary thinking trains to ask « why » questions and to provide logical and plausible answers. It can shed some light on a diversity of general problems such as how to distinguish homologies from analogies, the costs and benefits of multicellularity, the origin of novel structures (e.g. the head), or the evolution of sexual reproduction. In the next decade, we may expect a progressive convergence between developmental genetics and quantitative genetics.

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