scholarly journals Epigenetics in Insects: Genome Regulation and the Generation of Phenotypic Diversity

2019 ◽  
Vol 64 (1) ◽  
pp. 185-203 ◽  
Author(s):  
Karl M. Glastad ◽  
Brendan G. Hunt ◽  
Michael A.D. Goodisman
Keyword(s):  
Cellular Differentiation ◽  
Developmental Plasticity ◽  
Phenotypic Diversity ◽  
Epigenetic Inheritance ◽  
Evolutionary Significance ◽  
Epigenetic Information ◽  
Form And Function ◽  
Methylation Of Dna ◽  
Genome Regulation ◽  
And Function

Epigenetic inheritance is fundamentally important to cellular differentiation and developmental plasticity. In this review, we provide an introduction to the field of molecular epigenetics in insects. Epigenetic information is passed across cell divisions through the methylation of DNA, the modification of histone proteins, and the activity of noncoding RNAs. Much of our knowledge of insect epigenetics has been gleaned from a few model species. However, more studies of epigenetic information in traditionally nonmodel taxa will help advance our understanding of the developmental and evolutionary significance of epigenetic inheritance in insects. To this end, we also provide a brief overview of techniques for profiling and perturbing individual facets of the epigenome. Doing so in diverse cellular, developmental, and taxonomic contexts will collectively help shed new light on how genome regulation results in the generation of diversity in insect form and function.

scholarly journals Gene body methylation mediates epigenetic inheritance of plant traits

2021 ◽  
Author(s):  
Zaigham Shahzad ◽  
Jonathan D. Moore ◽  
Daniel Zilberman
Keyword(s):  
Gene Expression ◽  
Flowering Time ◽  
Cytosine Methylation ◽  
Plant Traits ◽  
Phenotypic Diversity ◽  
Strong Association ◽  
Epigenetic Inheritance ◽  
Evolutionary Significance ◽  
Gene Body ◽  
Gene Body Methylation

AbstractCytosine methylation is an epigenetically heritable DNA modification common in plant and animal genes, but the functional and evolutionary significance of gene body methylation (gbM) has remained enigmatic. Here we show that gbM enhances gene expression in Arabidopsis thaliana. We also demonstrate that natural gbM variation influences drought and heat tolerance and flowering time by modulating gene expression, including that of Flowering Locus C (FLC). Notably, epigenetic variation accounts for as much trait heritability in natural populations as DNA sequence polymorphism. Furthermore, we identify gbM variation in numerous genes associated with environmental variables, including a strong association between flowering time, spring atmospheric NO2 – a by-product of fossil fuel burning – and FLC epialleles. Our study demonstrates that gbM is an important modulator of gene expression, and its natural variation fundamentally shapes phenotypic diversity in plant populations. Thus, gbM provides an epigenetic basis for adaptive evolution independent of genetic polymorphism.

scholarly journals Morphology and behaviour: functional links in development and evolution

2011 ◽  
Vol 366 (1574) ◽  
pp. 2056-2068 ◽  
Author(s):  
Rinaldo C. Bertossa
Keyword(s):  
Phenotypic Diversity ◽  
Decisive Role ◽  
Evolutionary Developmental Biology ◽  
Form And Function ◽  
Biological Hierarchy ◽  
Object Of Study ◽  
And Function ◽  
Evo Devo ◽  
Versus Behaviour ◽  
Development And Evolution

Development and evolution of animal behaviour and morphology are frequently addressed independently, as reflected in the dichotomy of disciplines dedicated to their study distinguishing object of study (morphology versus behaviour) and perspective (ultimate versus proximate). Although traits are known to develop and evolve semi-independently, they are matched together in development and evolution to produce a unique functional phenotype. Here I highlight similarities shared by both traits, such as the decisive role played by the environment for their ontogeny. Considering the widespread developmental and functional entanglement between both traits, many cases of adaptive evolution are better understood when proximate and ultimate explanations are integrated. A field integrating these perspectives is evolutionary developmental biology (evo-devo), which studies the developmental basis of phenotypic diversity. Ultimate aspects in evo-devo studies—which have mostly focused on morphological traits—could become more apparent when behaviour, ‘the integrator of form and function’, is integrated into the same framework of analysis. Integrating a trait such as behaviour at a different level in the biological hierarchy will help to better understand not only how behavioural diversity is produced, but also how levels are connected to produce functional phenotypes and how these evolve. A possible framework to accommodate and compare form and function at different levels of the biological hierarchy is outlined. At the end, some methodological issues are discussed.

scholarly journals Reproductive Ontogeny and the Evolution of Morphological Diversity in Conifers and Other Plants

2019 ◽  
Vol 59 (3) ◽  
pp. 548-558 ◽  
Author(s):  
A B Leslie ◽  
J M Losada
Keyword(s):  
Morphological Evolution ◽  
Morphological Diversity ◽  
Developmental Rate ◽  
Reproductive Organs ◽  
Developmental Trajectory ◽  
Evolutionary Significance ◽  
Developmental Patterns ◽  
Functional Roles ◽  
Form And Function ◽  
And Function

Abstract Biologists often study morphological evolution through form and function relationships. But biological structures can perform multiple functional roles, complicating efforts to understand the evolutionary significance of any one relationship. Plant reproductive organs perform multiple roles in a sequence, however, which provides a unique opportunity to understand how structures evolve to meet multiple functional demands. Using conifers as a study group, we discuss how a shared developmental trajectory links the performance of sequential functional roles. Variation in development among lineages can underlie morphological diversity; pollination-stage seed cones in Pinaceae conifers function similarly but show diverse forms reflecting differences in developmental rate. As cones develop further, the morphologies that they use to perform later functional roles are influenced by the specific developmental patterns used to meet earlier demands, which may ultimately limit morphological diversity. However, we also show how selective pressures relating to the final functional stage (seed dispersal) may influence cone anatomy and morphology over all previous stages, highlighting the complex linkages among form, function, and development. We end by discussing the potential relationships between functional ontogeny and morphological disparity in plant reproductive structures more broadly, suggesting that the complex functional roles associated with seed plant reproduction probably underlie the high disparity in this group.

scholarly journals Vestigial mediates the effect of insulin signaling pathway on wing-morph switching in planthoppers

PLoS Genetics ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. e1009312
Author(s):  
Jin-Li Zhang ◽  
Sheng-Jie Fu ◽  
Sun-Jie Chen ◽  
Hao-Hao Chen ◽  
Yi-Lai Liu ◽  
...  
Keyword(s):  
Developmental Plasticity ◽  
Phenotypic Diversity ◽  
Evolutionary Significance ◽  
Signaling Cascade ◽  
Growth Factor Signaling ◽  
Wing Polymorphism ◽  
Forkhead Transcription Factor ◽  
Nymphal Stage

Wing polymorphism is an evolutionary feature found in a wide variety of insects, which offers a model system for studying the evolutionary significance of dispersal. In the wing-dimorphic planthopper Nilaparvata lugens, the insulin/insulin-like growth factor signaling (IIS) pathway acts as a ‘master signal’ that directs the development of either long-winged (LW) or short-winged (SW) morphs via regulation of the activity of Forkhead transcription factor subgroup O (NlFoxO). However, downstream effectors of the IIS–FoxO signaling cascade that mediate alternative wing morphs are unclear. Here we found that vestigial (Nlvg), a key wing-patterning gene, is selectively and temporally regulated by the IIS–FoxO signaling cascade during the wing-morph decision stage (fifth-instar stage). RNA interference (RNAi)-mediated silencing of Nlfoxo increase Nlvg expression in the fifth-instar stage (the last nymphal stage), thereby inducing LW development. Conversely, silencing of Nlvg can antagonize the effects of IIS activity on LW development, redirecting wing commitment from LW to the morph with intermediate wing size. In vitro and in vivo binding assays indicated that NlFoxO protein may suppress Nlvg expression by directly binding to the first intron region of the Nlvg locus. Our findings provide a first glimpse of the link connecting the IIS pathway to the wing-patterning network on the developmental plasticity of wings in insects, and help us understanding how phenotypic diversity is generated by the modification of a common set of pattern elements.

Fashioning the vertebrate heart: earliest embryonic decisions

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2099-2117 ◽  
Author(s):  
M.C. Fishman ◽  
K.R. Chien
Keyword(s):  
Caenorhabditis Elegans ◽  
Progenitor Cells ◽  
Cell Fate ◽  
Cellular Differentiation ◽  
Higher Order ◽  
Pattern Generation ◽  
Heart Tube ◽  
Form And Function ◽  
Heart Field ◽  
And Function

Our goal here is to set out the types of unitary decisions made by heart progenitor cells, from their appearance in the heart field until they form the simple heart tube. This provides a context to evaluate cell fate, lineage and, finally, morphogenetic decisions that configure global heart form and function. Some paradigms for cellular differentiation and for pattern generation may be borrowed from invertebrates, but neither Drosophila nor Caenorhabditis elegans suffice to unravel higher order decisions. Genetic analyses in mouse and zebrafish may provide one entrance to these pathways.

scholarly journals Parental effects in ecology and evolution: mechanisms, processes and implications

2009 ◽  
Vol 364 (1520) ◽  
pp. 1169-1177 ◽  
Author(s):  
Alexander V Badyaev ◽  
Tobias Uller
Keyword(s):  
Natural Selection ◽  
Epigenetic Inheritance ◽  
Life Cycles ◽  
Parental Effects ◽  
Developmental Systems ◽  
Form And Function ◽  
Composite Nature ◽  
Evolution By Natural Selection ◽  
And Function ◽  
Developmental Dynamics

As is the case with any metaphor, parental effects mean different things to different biologists—from developmental induction of novel phenotypic variation to an evolved adaptation, and from epigenetic transference of essential developmental resources to a stage of inheritance and ecological succession. Such a diversity of perspectives illustrates the composite nature of parental effects that, depending on the stage of their expression and whether they are considered a pattern or a process, combine the elements of developmental induction, homeostasis, natural selection, epigenetic inheritance and historical persistence. Here, we suggest that by emphasizing the complexity of causes and influences in developmental systems and by making explicit the links between development, natural selection and inheritance, the study of parental effects enables deeper understanding of developmental dynamics of life cycles and provides a unique opportunity to explicitly integrate development and evolution. We highlight these perspectives by placing parental effects in a wider evolutionary framework and suggest that far from being only an evolved static outcome of natural selection, a distinct channel of transmission between parents and offspring, or a statistical abstraction, parental effects on development enable evolution by natural selection by reliably transferring developmental resources needed to reconstruct, maintain and modify genetically inherited components of the phenotype. The view of parental effects as an essential and dynamic part of an evolutionary continuum unifies mechanisms behind the origination, modification and historical persistence of organismal form and function, and thus brings us closer to a more realistic understanding of life's complexity and diversity.

scholarly journals Fracture mechanics, enamel thickness and the evolution of molar form in hominins

2020 ◽  
Vol 16 (1) ◽  
pp. 20190671 ◽  
Author(s):  
Gary T. Schwartz ◽  
Amanda McGrosky ◽  
David S. Strait
Keyword(s):  
Fracture Mechanics ◽  
Oral Cavity ◽  
Functional Anatomy ◽  
Evolutionary Significance ◽  
Misleading Information ◽  
Enamel Thickness ◽  
Form And Function ◽  
Fossil Hominins ◽  
And Function

As the tissue most directly responsible for breaking down food in the oral cavity, the form and function of enamel is obviously of evolutionary significance in humans, non-human primates and other vertebrates. Accordingly, a standard metric, relative enamel thickness (RET), has been used for many decades to provide insights into vertebrate and human palaeobiology. Relatively thick enamel has evolved many times in vertebrates including hominoids (the group to which living humans and fossil hominins belong), and this pattern is thought to provide information about taxonomy, phylogeny, functional anatomy and diet. In particular, relatively thick enamel is thought to make tooth crowns strong so that they resist fractures associated with eating mechanically resistant foods. Here, we use current models of tooth biomechanics to show that RET is at best only moderately informative of function and diet in living hominoids and fossil hominins, and at worst provides misleading information. We propose a new metric, absolute crown strength, to assess the resistance of teeth to fracture, and identify what may be a novel characteristic of tooth strength in fossil hominins.

scholarly journals Recovery from transgenerational RNA silencing is driven by gene-specific homeostasis

2017 ◽  
Author(s):  
Sindhuja Devanapally ◽  
Pravrutha Raman ◽  
Samual Allgood ◽  
Farida Ettefa ◽  
Maigane Diop ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Epigenetic Inheritance ◽  
Target Sequence ◽  
C Elegans ◽  
Form And Function ◽  
Parental Exposure ◽  
Homologous Genes ◽  
In Trans ◽  
Successive Generations ◽  
And Function

AbstractChanges in gene expression that last for multiple generations without changes in gene sequence have been reported in many plants and animals1–3. Cases of such transgenerational epigenetic inheritance (TEI) could support the ancestral origins of some diseases and drive evolutionary novelty. Here, we report that stably expressed sequences in C. elegans have features that provide a barrier against TEI. By using double-stranded RNA (dsRNA) targeting the same sequence in different genes, we show that genes typically recover from silencing within the germline in a few generations. A rare recombinant two-gene operon containing this target sequence that recovered poorly from induced silencing enabled us to delineate mechanisms that can perpetuate silencing. Parental exposure to dsRNA targeting one gene within this operon reveals two distinct phases of the resulting TEI: only the matching gene is silenced in early generations, but both can become silenced in later generations. However, silencing of both genes can be initiated within one generation by mating, which perturbs intergenerational RNA-based mechanisms such that silencing dominates for more than 250 generations. This stable RNA silencing can also reduce the expression of homologous sequences in different genes in trans within the germline, but the homologous genes recover expression after a few generations. These results suggest that stably expressed sequences are subject to feedback control that opposes TEI initiated by multiple mechanisms within the germline. We speculate that similar homeostatic mechanisms that enable recovery from epigenetic changes underlie the observed preservation of form and function in successive generations of living systems.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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