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Villagra C, Frías-Lasserre D. Epigenetic Molecular Mechanisms in Insects. NEOTROPICAL ENTOMOLOGY 2020; 49:615-642. [PMID: 32514997 DOI: 10.1007/s13744-020-00777-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Insects are the largest animal group on Earth both in biomass and diversity. Their outstanding success has inspired genetics and developmental research, allowing the discovery of dynamic process explaining extreme phenotypic plasticity and canalization. Epigenetic molecular mechanisms (EMMs) are vital for several housekeeping functions in multicellular organisms, regulating developmental, ontogenetic trajectories and environmental adaptations. In Insecta, EMMs are involved in the development of extreme phenotypic divergences such as polyphenisms and eusocial castes. Here, we review the history of this research field and how the main EMMs found in insects help to understand their biological processes and diversity. EMMs in insects confer them rapid response capacity allowing insect either to change with plastic divergence or to keep constant when facing different stressors or stimuli. EMMs function both at intra as well as transgenerational scales, playing important roles in insect ecology and evolution. We discuss on how EMMs pervasive influences in Insecta require not only the control of gene expression but also the dynamic interplay of EMMs with further regulatory levels, including genetic, physiological, behavioral, and environmental among others, as was earlier proposed by the Probabilistic Epigenesis model and Developmental System Theory.
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Affiliation(s)
- C Villagra
- Instituto de Entomología, Univ Metropolitana de Ciencias de la Educación, Santiago, Chile.
| | - D Frías-Lasserre
- Instituto de Entomología, Univ Metropolitana de Ciencias de la Educación, Santiago, Chile
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Heestand B, Simon M, Frenk S, Titov D, Ahmed S. Transgenerational Sterility of Piwi Mutants Represents a Dynamic Form of Adult Reproductive Diapause. Cell Rep 2019; 23:156-171. [PMID: 29617657 PMCID: PMC5918633 DOI: 10.1016/j.celrep.2018.03.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/24/2018] [Accepted: 03/05/2018] [Indexed: 01/17/2023] Open
Abstract
Environmental stress can induce adult reproductive diapause, a state of developmental arrest that temporarily suspends reproduction. Deficiency for C. elegans Piwi protein PRG-1 results in strains that reproduce for many generations but then become sterile. We found that sterile-generation prg-1/Piwi mutants typically displayed pronounced germ cell atrophy as L4 larvae matured into 1-day-old adults. Atrophied germlines spontaneously reproliferated across the first days of adulthood, and this was accompanied by fertility for day 2–4 adults. Sterile day 5 prg-1 mutant adults remained sterile indefinitely, but providing an alternative food source could restore their fertility. Our data imply that late-generation prg-1 mutants experience a dynamic form of adult reproductive diapause, promoted by stress response, cell death, and RNAi pathways, where delayed fertility and reproductive quiescence represent parallel adaptive developmental outcomes. This may occur in response to a form of “heritable stress” that is transmitted by gametes and epigenetic in nature.
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Affiliation(s)
- Bree Heestand
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matt Simon
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Stephen Frenk
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Denis Titov
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Shawn Ahmed
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
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Abstract
Darwin's gemmules were supposed to be "thrown off" by cells and were "inconceivably minute and numerous as the stars in heaven." They were capable of self-propagation and diffusion from cell to cell, and circulation through the system. The word "gene" coined by Wilhelm Johannsen, was derived from de Vries's term "pangen," itself a substitute for "gemmule" in Darwin's Pangenesis. Johannsen resisted the "morphological" conception of genes as particles with a certain structure. Morgan's genes were considered to be stable entities arranged in an orderly linear pattern on chromosomes, like beads on a string. In the late 1940s, McClintock challenged the concept of the stability of the gene when she discovered that some genes could move within a chromosome and between chromosomes. In 1948, Mandel and Metais reported the presence of cell-free nucleic acids in human blood for the first time. Over the past several decades, it has been universally accepted that almost all types of cells not only shed molecules such as cell-free DNA (including genomic DNA, tumor DNA and fetal DNA), RNAs (including mRNA and small RNAs) and prions, but also release into the extracellular environment diverse types of membrane vesicles (known as extracellular vesicles) containing DNA, RNA and proteins. Thus Darwin's speculative gemmules of the 19th century have become the experimentally demonstrated circulating cell-free DNA, mobile RNAs, prions and extracellular vesicles.
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Affiliation(s)
- Yongsheng Liu
- Henan Collaborative Innovation Center of Modern Biological Breeding, Henan Institute of Science and Technology, Xinxiang, China; Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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Akkerman KC, Sattarin A, Kelly JK, Scoville AG. Transgenerational plasticity is sex-dependent and persistent in yellow monkeyflower ( Mimulus guttatus). ENVIRONMENTAL EPIGENETICS 2016; 2:dvw003. [PMID: 29492285 PMCID: PMC5804517 DOI: 10.1093/eep/dvw003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/16/2015] [Accepted: 01/27/2016] [Indexed: 05/19/2023]
Abstract
Transgenerational phenotypic plasticity, whereby environmental cues experienced by parents alter the phenotype of their progeny, has now been documented in diverse organisms. Transmission of environmentally determined responses is known to occur through both maternal and paternal gametes, but the underlying mechanisms have rarely been compared. In addition, the persistence of induction over multiple generations appears to vary widely, but has been characterized for relatively few systems. Yellow monkeyflower (Mimulus guttatus) is known to exhibit transgenerational induction of increased glandular trichome production in response to simulated insect damage. Here, we test for differences between maternal and paternal transmission of this response and examine its persistence over five generations following damage. Maternal and paternal damage resulted in similar and apparently additive increases in progeny trichome production. Treatment of germinating seeds with the genome-wide demethylating agent 5-azacytidine erased the effect of maternal but not paternal damage. The number of glandular trichomes remained elevated for three generations following damage. These results indicate that transgenerational transmission occurs through both maternal and paternal germ lines, but that they differ in the proximate mechanism of epigenetic inheritance. Our results also indicate that a wounding response can persist for multiple generations in the absence of subsequent damage.
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Affiliation(s)
- Kayla C. Akkerman
- Department of Biology, Central Washington University, Ellensburg, WA 98926, USA
| | - Arash Sattarin
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
| | - Alison G. Scoville
- Department of Biology, Central Washington University, Ellensburg, WA 98926, USA
- *Correspondence address. Department of Biology, Central Washington University, Ellensburg, 400 E University Way, Ellensburg, WA, 98926. Tel: 509-963-2802. Fax: 509-963-2730 E-mail:
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Sharma A. Systems genomics analysis centered on epigenetic inheritance supports development of a unified theory of biology. J Exp Biol 2015; 218:3368-73. [DOI: 10.1242/jeb.125922] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/20/2015] [Indexed: 12/18/2022]
Abstract
New discoveries are increasingly demanding integration of epigenetics, molecular biology, genomic networks, and physiology with evolution. This article provides a proof of concept for evolutionary transgenerational systems biology, proposed recently in the context of epigenetic inheritance in mammals. Gene set enrichment analysis of available genome level mammalian data presented here seems consistent with the concept that (1) heritable information about environmental effects in somatic cells is communicated to the germline by circulating microRNAs (miRNAs) or other RNAs released in physiological fluids, (2) epigenetic factors including miRNA-like small RNAs, DNA methylation and histone modifications are propagated across generations via gene networks, and (3) inherited epigenetic variations in the form of methylated cytosines are fixed in the population as thymines in evolutionary time course. The analysis supports integration of physiology and epigenetics with inheritance and evolution. This may catalyze efforts to develop a unified theory of biology.
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Affiliation(s)
- Abhay Sharma
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Sukhdev Vihar, Mathura Road, New Delhi 110025, India
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