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Kittelmann M, McGregor AP. Looking across the gap: Understanding the evolution of eyes and vision among insects. Bioessays 2024; 46:e2300240. [PMID: 38593308 DOI: 10.1002/bies.202300240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 04/11/2024]
Abstract
The compound eyes of insects exhibit stunning variation in size, structure, and function, which has allowed these animals to use their vision to adapt to a huge range of different environments and lifestyles, and evolve complex behaviors. Much of our knowledge of eye development has been learned from Drosophila, while visual adaptations and behaviors are often more striking and better understood from studies of other insects. However, recent studies in Drosophila and other insects, including bees, beetles, and butterflies, have begun to address this gap by revealing the genetic and developmental bases of differences in eye morphology and key new aspects of compound eye structure and function. Furthermore, technical advances have facilitated the generation of high-resolution connectomic data from different insect species that enhances our understanding of visual information processing, and the impact of changes in these processes on the evolution of vision and behavior. Here, we review these recent breakthroughs and propose that future integrated research from the development to function of visual systems within and among insect species represents a great opportunity to understand the remarkable diversification of insect eyes and vision.
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Affiliation(s)
- Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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2
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Truman JW, Riddiford LM, Konopova B, Nouzova M, Noriega FG, Herko M. The embryonic role of juvenile hormone in the firebrat, Thermobia domestica, reveals its function before its involvement in metamorphosis. eLife 2024; 12:RP92643. [PMID: 38568859 PMCID: PMC10994664 DOI: 10.7554/elife.92643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.
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Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
- Department of Biology, University of WashingtonSeattleUnited States
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
- Department of Biology, University of WashingtonSeattleUnited States
| | - Barbora Konopova
- Department of Zoology, Faculty of Science, University of South BohemiaCeske BudejoviceCzech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of SciencesCeske BudejoviceCzech Republic
| | - Marcela Nouzova
- Institute of Parasitology, Biology Centre of the Czech Academy of SciencesCeske BudejoviceCzech Republic
| | - Fernando G Noriega
- Department of Biological Sciences and BSI, Florida International UniversityMiamiUnited States
- Department of Parasitology, Faculty of Science, University of South BohemiaCeské BudejoviceCzech Republic
| | - Michelle Herko
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
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Truman JW, Riddiford LM, Konopová B, Nouzova M, Noriega FG, Herko M. The embryonic role of juvenile hormone in the firebrat, Thermobia domestica, reveals its function before its involvement in metamorphosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561279. [PMID: 37873170 PMCID: PMC10592639 DOI: 10.1101/2023.10.06.561279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.
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Affiliation(s)
- James W. Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Lynn M. Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Barbora Konopová
- Department of Zoology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Marcela Nouzova
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Fernando G. Noriega
- Department of Biological Sciences and BSI, Florida International University, FL ,USA
- Department of Parasitology, Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic
| | - Michelle Herko
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
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Chen Q, Sasikala-Appukuttan AK, Husain Z, Shrivastava A, Spain M, Sendler ED, Daines B, Fischer S, Chen R, Cook TA, Friedrich M. Global Gene Expression Analysis Reveals Complex Cuticle Organization of the Tribolium Compound Eye. Genome Biol Evol 2023; 15:evac181. [PMID: 36575057 PMCID: PMC9866248 DOI: 10.1093/gbe/evac181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/08/2022] [Accepted: 12/17/2022] [Indexed: 12/29/2022] Open
Abstract
The red flour beetle Tribolium castaneum is a resource-rich model for genomic and developmental studies. To extend previous studies on Tribolium eye development, we produced transcriptomes for normal-eyed and eye-depleted heads of pupae and adults to identify differentially transcript-enriched (DE) genes in the visual system. Unexpectedly, cuticle-related genes were the largest functional class in the pupal compound eye DE gene population, indicating differential enrichment in three distinct cuticle components: clear lens facet cuticle, highly melanized cuticle of the ocular diaphragm, which surrounds the Tribolium compound eye for internal fortification, and newly identified facet margins of the tanned cuticle, possibly enhancing external fortification. Phylogenetic, linkage, and high-throughput gene knockdown data suggest that most cuticle proteins (CPs) expressed in the Tribolium compound eye stem from the deployment of ancient CP genes. Consistent with this, TcasCPR15, which we identified as the major lens CP gene in Tribolium, is a beetle-specific but pleiotropic paralog of the ancient CPR RR-2 CP gene family. The less abundant yet most likely even more lens-specific TcasCP63 is a member of a sprawling family of noncanonical CP genes, documenting a role of local gene family expansions in the emergence of the Tribolium compound eye CP repertoire. Comparisons with Drosophila and the mosquito Anopheles gambiae reveal a steady turnover of lens-enriched CP genes during insect evolution.
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Affiliation(s)
- Qing Chen
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | | | - Zahabiya Husain
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | - Anura Shrivastava
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | - Marla Spain
- Center of Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Edward D Sendler
- Center of Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Bryce Daines
- Department of Molecular and Human Genetics, Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Stefan Fischer
- Evolutionary Biology of Invertebrates, Institute of Evolution and Ecology, University of Tübingen, Germany
| | - Rui Chen
- Evolutionary Biology of Invertebrates, Institute of Evolution and Ecology, University of Tübingen, Germany
| | - Tiffany A Cook
- Center of Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, USA
- Department of Ophthalmological, Visual, and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
- Department of Ophthalmological, Visual, and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, USA
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McCulloch KJ, Macias-Muñoz A, Briscoe AD. Insect opsins and evo-devo: what have we learned in 25 years? Philos Trans R Soc Lond B Biol Sci 2022; 377:20210288. [PMID: 36058243 PMCID: PMC9441233 DOI: 10.1098/rstb.2021.0288] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/16/2022] [Indexed: 12/16/2022] Open
Abstract
The visual pigments known as opsins are the primary molecular basis for colour vision in animals. Insects are among the most diverse of animal groups and their visual systems reflect a variety of life histories. The study of insect opsins in the fruit fly Drosophila melanogaster has led to major advances in the fields of neuroscience, development and evolution. In the last 25 years, research in D. melanogaster has improved our understanding of opsin genotype-phenotype relationships while comparative work in other insects has expanded our understanding of the evolution of insect eyes via gene duplication, coexpression and homologue switching. Even so, until recently, technology and sampling have limited our understanding of the fundamental mechanisms that evolution uses to shape the diversity of insect eyes. With the advent of genome editing and in vitro expression assays, the study of insect opsins is poised to reveal new frontiers in evolutionary biology, visual neuroscience, and animal behaviour. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.
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Affiliation(s)
- Kyle J. McCulloch
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108, USA
| | - Aide Macias-Muñoz
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Adriana D. Briscoe
- Department of Ecology and Evolutionary Biology, University of California, 321 Steinhaus Hall, Irvine, CA 92697, USA
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Ultrastructure of the larval eyes of the hangingfly Terrobittacus implicatus (Mecoptera: Bittacidae). Micron 2021; 152:103176. [PMID: 34763214 DOI: 10.1016/j.micron.2021.103176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 10/31/2021] [Accepted: 10/31/2021] [Indexed: 11/23/2022]
Abstract
The fine structure of the larval eyes of the hangingfly Terrobittacus implicatus (Huang & Hua) was investigated using scanning and transmission electron microscopy. The results show that the larval eyes of T. implicatus each consist of seven spaced ommatidia. Each ommatidium is composed of a corneal lens with about 45 lamellae, a tetrapartite eucone type of crystalline cone, eight retinula cells, two primary pigment cells, and an undetermined number of secondary pigment cells. The rhabdomeres of eight retinula cells effectively fuse into a centrally-fused, tiered funnel-shaped rhabdom extending from the base of the crystalline cone deeply into the ommatidium. In light of different positions in the ommatidium, the retinula cells can be divided into four distal and four proximal retinula cells. Pigment cells envelop the entire ommatidium. Electron-lucent vesicles are abundant throughout the cytoplasm of the eight retinula cells. The larval ommatidia of T. implicatus are similar to those of the Panorpidae, except for the distal retinula cells that also participate in the formation of the proximal rhabdom. In this case, the larval eyes of T. implicatus may lie in the transitional stage during the larval eye evolution of insects from ommatidia to stemmata.
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Mishra AK, Fritsch C, Voutev R, Mann RS, Sprecher SG. Homothorax controls a binary Rhodopsin switch in Drosophila ocelli. PLoS Genet 2021; 17:e1009460. [PMID: 34314427 PMCID: PMC8345863 DOI: 10.1371/journal.pgen.1009460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 08/06/2021] [Accepted: 07/02/2021] [Indexed: 11/26/2022] Open
Abstract
Visual perception of the environment is mediated by specialized photoreceptor (PR) neurons of the eye. Each PR expresses photosensitive opsins, which are activated by a particular wavelength of light. In most insects, the visual system comprises a pair of compound eyes that are mainly associated with motion, color or polarized light detection, and a triplet of ocelli that are thought to be critical during flight to detect horizon and movements. It is widely believed that the evolutionary diversification of compound eye and ocelli in insects occurred from an ancestral visual organ around 500 million years ago. Concurrently, opsin genes were also duplicated to provide distinct spectral sensitivities to different PRs of compound eye and ocelli. In the fruit fly Drosophila melanogaster, Rhodopsin1 (Rh1) and Rh2 are closely related opsins that originated from the duplication of a single ancestral gene. However, in the visual organs, Rh2 is uniquely expressed in ocelli whereas Rh1 is uniquely expressed in outer PRs of the compound eye. It is currently unknown how this differential expression of Rh1 and Rh2 in the two visual organs is controlled to provide unique spectral sensitivities to ocelli and compound eyes. Here, we show that Homothorax (Hth) is expressed in ocelli and confers proper rhodopsin expression. We find that Hth controls a binary Rhodopsin switch in ocelli to promote Rh2 expression and repress Rh1 expression. Genetic and molecular analysis of rh1 and rh2 supports that Hth acts through their promoters to regulate Rhodopsin expression in the ocelli. Finally, we also show that when ectopically expressed in the retina, hth is sufficient to induce Rh2 expression only at the outer PRs in a cell autonomous manner. We therefore propose that the diversification of rhodpsins in the ocelli and retinal outer PRs occurred by duplication of an ancestral gene, which is under the control of Homothorax. Sensory perception of light is mediated by specialized photoreceptor neurons of the eye. Each photoreceptor expresses unique photopigments called opsins and they are sensitive to particular wavelengths of light. In insects, ocelli and compound eyes are the main photosensory organs and they express different opsins. It is believed that opsins were duplicated during evolution to provide specificity to ocelli and the compound eye and this is corelated with their distinct functions. We show that Homothorax acts to control a binary Rhodopsin switch in the fruit fly Drosophila melanogaster to promote Rhodopsin 2 expression and represses Rhodopsin 1 expression in the ocelli. Genetic and molecular analysis showed that Homothorax acts through the promoters of rhosopsin 1 and rhosopsin 2 and controls their expression in the ocelli. We also show that Hth binding sites in the promoter region of rhodopsin 1 and rhodopsin 2 are conserved between different Drosophila species. We therefore proposed that Hth may have acted as a critical determinant during evolution which was required to provide specificity to the ocelli and compound eye by regulating a binary Rhodopsin switch in the ocelli.
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Affiliation(s)
- Abhishek Kumar Mishra
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail: (AKM); (SGS)
| | - Cornelia Fritsch
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Roumen Voutev
- Department of Biochemistry and Molecular Biophysics and Neuroscience, Mortimer B. Zukerman Mind Brain Behavior Institute, Columbia University, New York, United States of America
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics and Neuroscience, Mortimer B. Zukerman Mind Brain Behavior Institute, Columbia University, New York, United States of America
| | - Simon G. Sprecher
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail: (AKM); (SGS)
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Lobo-Cabrera FJ, Navarro T, Iannini A, Casares F, Cuetos A. Quantitative Relationships Between Growth, Differentiation, and Shape That Control Drosophila Eye Development and Its Variation. Front Cell Dev Biol 2021; 9:681933. [PMID: 34350178 PMCID: PMC8326509 DOI: 10.3389/fcell.2021.681933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/24/2021] [Indexed: 11/30/2022] Open
Abstract
The size of organs is critical for their function and often a defining trait of a species. Still, how organs reach a species-specific size or how this size varies during evolution are problems not yet solved. Here, we have investigated the conditions that ensure growth termination, variation of final size and the stability of the process for developmental systems that grow and differentiate simultaneously. Specifically, we present a theoretical model for the development of the Drosophila eye, a system where a wave of differentiation sweeps across a growing primordium. This model, which describes the system in a simplified form, predicts universal relationships linking final eye size and developmental time to a single parameter which integrates genetically-controlled variables, the rates of cell proliferation and differentiation, with geometrical factors. We find that the predictions of the theoretical model show good agreement with previously published experimental results. We also develop a new computational model that recapitulates the process more realistically and find concordance between this model and theory as well, but only when the primordium is circular. However, when the primordium is elliptical both models show discrepancies. We explain this difference by the mechanical interactions between cells, an aspect that is not included in the theoretical model. Globally, our work defines the quantitative relationships between rates of growth and differentiation and organ primordium size that ensure growth termination (and, thereby, specify final eye size) and determine the duration of the process; identifies geometrical dependencies of both size and developmental time; and uncovers potential instabilities of the system which might constraint developmental strategies to evolve eyes of different size.
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Affiliation(s)
| | - Tomás Navarro
- DMC2-GEM Unit, The CABD, CSIC-Pablo de Olavide University-JA, Seville, Spain
| | - Antonella Iannini
- DMC2-GEM Unit, The CABD, CSIC-Pablo de Olavide University-JA, Seville, Spain
| | - Fernando Casares
- DMC2-GEM Unit, The CABD, CSIC-Pablo de Olavide University-JA, Seville, Spain
| | - Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Sevilla, Spain
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Growing tiny eyes: How juvenile jumping spiders retain high visual performance in the face of size limitations and developmental constraints. Vision Res 2019; 160:24-36. [DOI: 10.1016/j.visres.2019.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 11/21/2022]
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Friedrich M. Ancient genetic redundancy of eyeless and twin of eyeless in the arthropod ocular segment. Dev Biol 2017; 432:192-200. [PMID: 28993201 DOI: 10.1016/j.ydbio.2017.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 01/28/2023]
Abstract
Pax6 transcription factors are essential upstream regulators in the developing anterior brain and peripheral visual system of most bilaterian animals. While a single homolog is in charge of these functions in vertebrates, two Pax6 genes are in Drosophila: eyeless (ey) and twin of eyeless (toy). At first glance, their co-existence seems sufficiently explained by their differential involvement in the specification of two types of insect visual organs: the lateral compound eyes (ey) and the dorsal ocelli (toy). Less straightforward to understand, however, is their genetic redundancy in promoting defined early and late growth phases of the precursor tissue to these organs: the eye-antennal imaginal disc. Drawing on comparative sequence, expression, and gene function evidence, I here conclude that this gene regulatory network module dates back to the dawn of arthropod evolution, securing the embryonic development of the ocular head segment. Thus, ey and toy constitute a paradigm to explore the organization and functional significance of longterm conserved genetic redundancy of duplicated genes. Indeed, as first steps in this direction, recent studies uncovered the shared use of binding sites in shared enhancers of target genes that are under redundant (string) and, strikingly, even subfunctionalized control by ey and toy (atonal). Equally significant, the evolutionarily recent and paralog-specific function of ey to repress the transcription of the antenna fate regulator Distal-less offers a functionally and phylogenetically well-defined opportunity to study the reconciliation of shared, partitioned, and newly acquired functions in a duplicated developmental gene pair.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201,USA.
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Marco Antonio DS, Hartfelder K. Toward an Understanding of Divergent Compound Eye Development in Drones and Workers of the Honeybee (Apis melliferaL.): A Correlative Analysis of Morphology and Gene Expression. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:139-156. [DOI: 10.1002/jez.b.22696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 08/17/2016] [Accepted: 08/21/2016] [Indexed: 12/27/2022]
Affiliation(s)
- David S. Marco Antonio
- Departamento de Genética; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
| | - Klaus Hartfelder
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
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Compound eye formation in the termite Incisitermes minor (Isoptera: Kalotermitidae). Dev Genes Evol 2015; 225:235-51. [PMID: 26155777 DOI: 10.1007/s00427-015-0507-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
Abstract
The postembryonic development and caste differentiation patterns of lower termites have been described multiple times in a variety of different species. However, most of these studies focused on gross ontogeny, without carefully describing the maturation of any particular organ or organ system. The few studies that have attempted to correlate caste development and organ differentiation have produced somewhat inconsistent results, especially in the area of eye formation. Therefore, in order to help further elucidate the relationship between eye formation and postembryonic differentiation in lower termites, we studied eye development in the termite, Incisitermes minor (Hagen). Eye formation in I. minor began in the earliest larvae, with only an eye primordium. However, in all later larval stages, characteristic eye structures were observed and were shown to progressively differentiate through larval and nymphal stages. Curiously, pigmentation began with three to eight groups of cells in early larvae and the number of these pigmented groups increased along the developmental time course. Ultimately, a uniformly pigmented eye area was formed by the early nymphal stage. The overall eye area also gradually increased along with normal caste development, but the characteristic lenses seen in a prototypical insect compound eye did not completely form until after the final nymphal stage. Electrophysiological measurements provided clear evidence that eyes were indeed functional at all stages of development where pigment was present. Based upon this data, the eye development pattern in I. minor appeared to follow a divergent pathway from holometabolous insects and an intermediate pathway between typical hemimetabolous eye development and the heterochronic shift observed in other termite species.
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Molecular characterization and embryonic origin of the eyes in the common house spider Parasteatoda tepidariorum. EvoDevo 2015; 6:15. [PMID: 26034574 PMCID: PMC4450840 DOI: 10.1186/s13227-015-0011-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/10/2015] [Indexed: 01/30/2023] Open
Abstract
Background Two visual systems are present in most arthropod groups: median and lateral eyes. Most of our current knowledge about the developmental and molecular mechanisms involved in eye formation in arthropods comes from research in the model system Drosophila melanogaster. Here, a core set of retinal determination genes, namely, sine-oculis (so), eyes absent (eya), dachshund (dac), and the two pax6 orthologues eyeless (ey) and twin of eyeless (toy) govern early retinal development. By contrast, not much is known about the development of the up-to-eight eyes present in spiders. Therefore, we analyzed the embryonic expression of core retinal determination genes in the common house spider Parasteatoda tepidariorum. Results We show that the anlagen of the median and lateral eyes in P. tepidariorum originate from different regions of the non-neurogenic ectoderm in the embryonic head. The median eyes are specified as two individual anlagen in an anterior median position in the developing head and subsequently move to their final position following extensive morphogenetic movements of the non-neurogenic ectoderm. The lateral eyes develop from a more lateral position. Intriguingly, they are specified as a unique field of cells that splits into the three individual lateral eyes during late embryonic development. Using gene expression analyses, we identified a unique combination of determination gene expression in the anlagen of the lateral and median eyes, respectively. Conclusions This study of retinal determination genes in the common house spider P. tepidariorum represents the first comprehensive analysis of the well-known retinal determination genes in arthropods outside insects. The development of the individual lateral eyes via the subdivision of one single eye primordium might be the vestige of a larger composite eye anlage, and thus supports the notion that the composite eye is the plesiomorphic state of the lateral eyes in arthropods. The molecular distinction of the two visual systems is similar to the one described for compound eyes and ocelli in Drosophila, suggesting that a unique core determination network for median and lateral eyes, respectively, might have been in place already in the last common ancestor of spiders and insects. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0011-9) contains supplementary material, which is available to authorized users.
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Luan Q, Chen Q, Friedrich M. The Pax6 genes eyeless and twin of eyeless are required for global patterning of the ocular segment in the Tribolium embryo. Dev Biol 2014; 394:367-81. [PMID: 25149513 DOI: 10.1016/j.ydbio.2014.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 06/23/2014] [Accepted: 08/06/2014] [Indexed: 01/08/2023]
Abstract
The transcription factor gene Pax6 is widely considered a master regulator of eye development in bilaterian animals. However, the existence of visual organs that develop without Pax6 input and the considerable pleiotropy of Pax6 outside the visual system dictate further studies into defining ancestral functions of this important regulator. Previous work has shown that the combinatorial knockdown of the insect Pax6 orthologs eyeless (ey) and twin of eyeless (toy) perturbs the development of the visual system but also other areas of the larval head in the red flour beetle Tribolium castaneum. To elucidate the role of Pax6 during Tribolium head development in more detail, we studied head cuticle morphology, brain anatomy, embryonic head morphogenesis, and developmental marker gene expression in combinatorial ey and toy knockdown animals. Our experiments reveal that Pax6 is broadly required for patterning the anterior embryonic head. One of the earliest detectable roles is the formation of the embryonic head lobes, which originate from within the ocular segment and give rise to large parts of the supraesophageal brain including the mushroom body, a part of the posterior head capsule cuticle, and the visual system. We present further evidence that toy continues to be required for the development of the larval eyes after formation of the embryonic head lobes in cooperation with the eye developmental transcription factor dachshund (dac). The sum of our findings suggests that Pax6 functions as a competence factor throughout the development of the insect ocular segment. Comparative evidence identifies this function as an ancestral aspect of bilaterian head development.
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Affiliation(s)
- Qing Luan
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403, USA
| | - Qing Chen
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201, USA.
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Takagi A, Kurita K, Terasawa T, Nakamura T, Bando T, Moriyama Y, Mito T, Noji S, Ohuchi H. Functional analysis of the role of eyes absent and sine oculis in the developing eye of the cricket Gryllus bimaculatus. Dev Growth Differ 2012; 54:227-40. [PMID: 22348272 DOI: 10.1111/j.1440-169x.2011.01325.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the cricket Gryllus bimaculatus, a hemimetabolous insect, the compound eyes begin to form in the embryo and increase 5-6 fold in size during the postembryonic development of the nymphal stage. Retinal stem cells in the anteroventral proliferation zone (AVPZ) of the nymphal eye proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. However, mechanisms underlying this type of eye formation have not been well elucidated yet. Here, we found that the homologues of the retinal determination transcription factor genes of eyes absent (eya) and sine oculis (so) are expressed during the cricket embryonic eye formation. eya is also expressed intensely in the AVPZ of the nymphal eye. To explore their functions, we performed knockdown by RNA interference (RNAi). Knockdown of Gb'eya resulted in loss of the embryonic eye. In the nymphal eye, RNAi against Gb'eya or Gb'so impaired retinal morphology by apparently transforming cornea structures into head cuticle. These results imply that Gb'eya and Gb'so are essential for the differentiation of the retinal progenitor cells and maintaining retinal structures during eye development.
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Affiliation(s)
- Akira Takagi
- Department of Life Systems, Institute of Technology and Science, University of Tokushima, 2-1 Minami-Jyosanjima-cho, Tokushima City 770-8506, Japan
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Keene AC, Sprecher SG. Seeing the light: photobehavior in fruit fly larvae. Trends Neurosci 2012; 35:104-10. [DOI: 10.1016/j.tins.2011.11.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 11/06/2011] [Accepted: 11/06/2011] [Indexed: 02/01/2023]
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Knorr E, Vilcinskas A. Post-embryonic functions of HSP90 in Tribolium castaneum include the regulation of compound eye development. Dev Genes Evol 2011; 221:357-62. [PMID: 22081039 DOI: 10.1007/s00427-011-0379-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/26/2011] [Indexed: 10/15/2022]
Abstract
Heat shock protein 90 (HSP90) belongs to a family of conserved chaperons with multiple roles in stress adaptation and development, including spermatogenesis, oogenesis and embryogenesis in insects. In the red flour beetle, Tribolium castaneum, we found that HSP90 is transiently upregulated during larval development, in prepupae, in female pupae and in adults, suggesting multiple post-embryonic roles. We found that silencing HSP90 expression by RNA interference was lethal within 10 days at all developmental stages. Titration experiments revealed that larvae were more susceptible than pupae or beetles. Interestingly, HSP90 silencing in final instar larvae resulted in abnormal pupal phenotypes lacking compound eyes and exhibiting prepupal features, suggesting developmental arrest at the prepupal stage. Our results suggest that HSP90 functions can be expanded beyond the known ones in insect embryogenesis to include roles in post-embryonic development such as the regulation of compound eye development.
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Affiliation(s)
- Eileen Knorr
- Institute of Phytopathology and Applied Zoology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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18
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Tsachaki M, Sprecher SG. Genetic and developmental mechanisms underlying the formation of theDrosophilacompound eye. Dev Dyn 2011; 241:40-56. [DOI: 10.1002/dvdy.22738] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2011] [Indexed: 01/15/2023] Open
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Friedrich M. Drosophila as a developmental paradigm of regressive brain evolution: proof of principle in the visual system. BRAIN, BEHAVIOR AND EVOLUTION 2011; 78:199-215. [PMID: 21893944 DOI: 10.1159/000329850] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/23/2011] [Indexed: 11/19/2022]
Abstract
Evolutionary developmental biology focuses heavily on the constructive evolution of body plan components, but there are many instances such as parasitism, cave adaptation, or postembryonic growth rate optimization where evolutionary regression is of adaptive value. This is particularly true in the nervous system because of its massive energy costs. However, comparatively little effort has thus far been made to understand the evolutionary developmental trajectories of adaptive nervous system reduction. This review focuses on the organization and evolution of the Drosophila larval brain, which represents an exceptional example of miniaturization, most dramatically in the visual system. It is specifically discussed how the dependency of outer optic lobe development on retinal innervation can be assumed to have facilitated a first evolutionary phase of larval visual system reduction. Afferent input-contingent development of neu- ral compartments very likely plays a widespread role in adaptive brain evolution. Understanding the complete deconstruction of the larval optic neuropiles in Drosophila awaits expanded comparative analysis but has the promise to inform about further developmental trajectories and mechanisms underlying regressive evolution of the brain.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, School of Medicine, Wayne State University, Detroit, MI 48202, USA. friedrichm @ wayne.edu
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ZarinKamar N, Yang X, Bao R, Friedrich F, Beutel R, Friedrich M. The Pax gene eyegone facilitates repression of eye development in Tribolium. EvoDevo 2011; 2:8. [PMID: 21463500 PMCID: PMC3082225 DOI: 10.1186/2041-9139-2-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 04/04/2011] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The Pax transcription factor gene eyegone (eyg) participates in many developmental processes in Drosophila, including the Notch signaling activated postembryonic growth of the eye primordium, global development of the adult head and the development of the antenna. In contrast to other Pax genes, the functional conservation of eyg in species other than Drosophila has not yet been explored. RESULTS We investigated the role of eyg during the postembryonic development of the red flour beetle Tribolium castaneum. Our results indicate conserved roles in antennal but not in eye development. Besides segmentation defects in the antenna, Tribolium eyg knockdown animals were characterized by eye enlargement due to the formation of surplus ommatidia at the central anterior edge of the compound eye. This effect resulted from the failure of the developing gena to locally repress retinal differentiation, which underlies the formation of the characteristic anterior notch in the Tribolium eye. Neither varying the induction time point of eyg knockdown nor knocking down components of the Janus kinase/Signal Transducer and Activators of Transcription signaling pathway in combination with eyg reduced eye size like in Drosophila. CONCLUSIONS Taken together, expression and knockdown data suggest that Tribolium eyg serves as a competence factor that facilitates the repression of retinal differentiation in response to an unknown signal produced in the developing gena. At the comparative level, our findings reveal diverged roles of eyg associated with the evolution of different modes of postembryonic head development in endopterygote insects as well as diversified head morphologies in darkling beetles.
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Affiliation(s)
- Nazanin ZarinKamar
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Xiaoyun Yang
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Riyue Bao
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Frank Friedrich
- Institut fur Spezielle Zoologie und Evolutionsbiologie, Friedrich Schiller Universitat Jena, Erbertstrasse 1, 07743 Jena, Germany
| | - Rolf Beutel
- Institut fur Spezielle Zoologie und Evolutionsbiologie, Friedrich Schiller Universitat Jena, Erbertstrasse 1, 07743 Jena, Germany
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA.,Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201, USA
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Dong Y, Friedrich M. Enforcing biphasic eye development in a directly developing insect by transient knockdown of single eye selector genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 314:104-14. [PMID: 19637278 DOI: 10.1002/jez.b.21313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The visual system of indirectly developing insects such as Drosophila passes through two phases of development. Larval eyes form in the embryo, whereas the adult compound eyes form during metamorphosis. Comparative evidence implies that this biphasic mode of visual system development evolved from the continuously developing eye of directly developing insects. We investigated the developmental basis of this evolutionary transformation in a directly developing insect taking advantage of the time-limited nature of systemic RNAi in the grasshopper Schistocerca americana. Transient knockdown of the homologs of the early retinal genes eyes absent (eya) or sine oculis (so) both induced long-term arrest of eye development in grasshopper nymphs. Eye development, however, resumed after knockdown expiry. This finding sheds first light on the molecular regulation of postembryonic eye development in directly developing insects and unravels an inherent capacity of the underlying gene regulatory network to accommodate for partitioning visual system development into discrete phases, as in indirectly developing insects.
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Affiliation(s)
- Ying Dong
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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22
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Melzer RR. Persisting stemma neuropils inChaoborus crystallinus(Diptera: Chaoboridae): Development and evolution of a bipartite visual system. J Morphol 2009; 270:1524-30. [DOI: 10.1002/jmor.10779] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Yang X, ZarinKamar N, Bao R, Friedrich M. Probing the Drosophila retinal determination gene network in Tribolium (I): The early retinal genes dachshund, eyes absent and sine oculis. Dev Biol 2009; 333:202-14. [DOI: 10.1016/j.ydbio.2009.02.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 12/24/2022]
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Yang X, Weber M, ZarinKamar N, Posnien N, Friedrich F, Wigand B, Beutel R, Damen WG, Bucher G, Klingler M, Friedrich M. Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless. Dev Biol 2009; 333:215-27. [DOI: 10.1016/j.ydbio.2009.06.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 05/18/2009] [Accepted: 06/07/2009] [Indexed: 11/15/2022]
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Zhao X, Coptis V, Farris SM. Metamorphosis and adult development of the mushroom bodies of the red flour beetle, Tribolium castaneum. Dev Neurobiol 2009; 68:1487-502. [PMID: 18792069 DOI: 10.1002/dneu.20669] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The insect mushroom bodies play important roles in a number of higher processing functions such as sensory integration, higher level olfactory processing, and spatial and associative learning and memory. These functions have been established through studies in a handful of tractable model systems, of which only the fruit fly Drosophila melanogaster has been readily amenable to genetic manipulations. The red flour beetle Tribolium castaneum has a sequenced genome and has been subject to the development of molecular tools for the ready manipulation of gene expression; however, little is known about the development and organization of the mushroom bodies of this insect. The present account bridges this gap by demonstrating that the organization of the Tribolium mushroom bodies is strikingly like that of the fruit fly, with the significant exception that the timeline of neurogenesis is shifted so that the last population of Kenyon cells is born entirely after adult eclosion. Tribolium Kenyon cells are generated by two large neuroblasts per hemisphere and segregate into an early-born delta lobe subpopulation followed by clear homologs of the Drosophila gamma, alpha'/beta' and alpha/beta lobe subpopulations, with the larval-born cohorts undergoing dendritic reorganization during metamorphosis. BrdU labeling and immunohistochemical staining also reveal that a proportion of individual Tribolium have variable numbers of mushroom body neuroblasts. If heritable, this variation represents a unique opportunity for further studies of the genetic control of brain region size through the control of neuroblast number and cell cycle dynamics.
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Affiliation(s)
- X Zhao
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506, USA
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26
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Rivera AS, Oakley TH. Ontogeny of sexual dimorphism via tissue duplication in an ostracod (Crustacea). Evol Dev 2009; 11:233-43. [DOI: 10.1111/j.1525-142x.2009.00323.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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27
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Nalepa CA, Maekawa K, Shimada K, Saito Y, Arellano C, Matsumoto T. Altricial Development in Subsocial Wood-Feeding Cockroaches. Zoolog Sci 2008; 25:1190-8. [DOI: 10.2108/zsj.25.1190] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Friedrich M. Opsins and cell fate in the Drosophila Bolwig organ: tricky lessons in homology inference. Bioessays 2008; 30:980-93. [PMID: 18800378 DOI: 10.1002/bies.20803] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Drosophila Bolwig organs are small photoreceptor bundles that facilitate the phototactic behavior of the larva. Comparative literature suggests that these highly reduced visual organs share evolutionary ancestry with the adult compound eye. A recent molecular genetic study produced the first detailed account of the mechanisms controlling differential opsin expression and photoreceptor subtype determination in these enigmatic eyes of the Drosophila larva. Here, the evolutionary implications are examined, taking into account the dynamic diversification of opsin genes and the spatial regulation of opsin homolog expression in other insects. It is concluded that, consistent with their common evolutionary roots, the Drosophila larval and adult eyes use the same mechanisms for the regulation of opsin expression and photoreceptor cell fate specification. Strikingly, the structurally highly derived Bolwig organs retained a more ancestral state of opsin expression and regulation. Inconspicuous in size, the Drosophila larval eyes deliver useful lessons in the reconstruction of homology between neuronal cell types with gene expression data, and on the conservative nature of gene regulatory network evolution during the emergence of novel organs from ancestral templates.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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29
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Oakley TH, Plachetzki DC, Rivera AS. Furcation, field-splitting, and the evolutionary origins of novelty in arthropod photoreceptors. ARTHROPOD STRUCTURE & DEVELOPMENT 2007; 36:386-400. [PMID: 18089117 DOI: 10.1016/j.asd.2007.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 08/28/2007] [Indexed: 05/25/2023]
Abstract
Arthropod photoreceptor evolution is a prime example of how evolution has used existing components in the origin of new structures. Here, we outline a comparative approach to understanding the mutational origins of novel structures, describing multiple examples from arthropod photoreceptor evolution. We suggest that developmental mechanisms have often split photoreceptors during evolution (field-splitting) and we introduce "co-duplication" as a null model for the mutational origins of photoreceptor components. Under co-duplication, gene duplication events coincide with the origin of a higher level structure like an eye. If co-duplication is rejected for a component, that component probably came to be used in a new photoreceptor through regulatory mutations. If not rejected, a gene duplication mutation may have allowed the component to be used in a new structure. In multiple case studies in arthropod photoreceptor evolution, we consistently reject the null hypothesis of co-duplication of genetic components and photoreceptors. Nevertheless, gene duplication events have in some cases occurred later, allowing divergence of photoreceptors. These studies provide a new perspective on the evolution of arthropod photoreceptors and provide a comparative approach that generalizes to the study of any evolutionary novelty.
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Affiliation(s)
- Todd H Oakley
- Ecology Evolution and Marine Biology, University of California-Santa Barbara, Santa Barbara, CA 93106, USA.
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Truman JW, Riddiford LM. The morphostatic actions of juvenile hormone. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2007; 37:761-70. [PMID: 17628276 DOI: 10.1016/j.ibmb.2007.05.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Revised: 05/14/2007] [Accepted: 05/15/2007] [Indexed: 05/16/2023]
Abstract
The maintenance of "status quo" in larvae by juvenile hormone (JH) involves both the programming of ecdysteroid-dependent synthesis during the molt and the suppression of morphogenetic growth during the intermolt. The latter morphostatic action does not require ecdysteroids, and has been studied in the formation of imaginal discs in Manduca sexta. Preultimate larval instars have both invaginated discs and imaginal primordia, both of which grow isomorphically with the larva. In the last instar, the young discs/primordia initiate the morphogenesis and patterning that results in a mature disc. JH suppresses both the initiation and progression of the signaling that transforms immature discs or primordia into a fully patterned imaginal disc. This transformation normally occurs in the context of the rapid growth of the last larval stage, and nutrient-dependent factors appear to be able to override the JH suppression. The morphostatic action of JH may have been important for the evolution of the larval stage. Studies on embryos of basal, hemimetabolous insects show that their premature exposure to JH can truncate patterning programs and cause precocious tissue maturation, factors essential for organizing a novel larval form. This suppression of embryonic patterning then results in embryonic fields that remain dormant as long as JH is present. These are the primordia that can transform into imaginal discs once JH disappears in preparation for metamorphosis.
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Affiliation(s)
- James W Truman
- Department of Biology, University of Washington, Seattle, WA 98195, USA.
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Morante J, Desplan C, Celik A. Generating patterned arrays of photoreceptors. Curr Opin Genet Dev 2007; 17:314-9. [PMID: 17616388 PMCID: PMC2713430 DOI: 10.1016/j.gde.2007.05.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 05/15/2007] [Accepted: 05/16/2007] [Indexed: 10/23/2022]
Abstract
One of the most fascinating topics in biology is to understand the development of highly differentiated cells such as photoreceptors (PRs). This process involves successive steps, starting with the generation of the eye primordium, recruitment and specification of PRs and finally, expression of the proper rhodopsin, the photopigment that initiates the signaling cascade underlying light input excitation. In this review, we describe the sequential steps that take place in the Drosophila eye, from the initial neuronal specification of PRs through their full maturation, focusing specifically on the transcription factors and signaling pathways involved in controlling the precise expression of different rhodopsins in specialized PRs.
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Affiliation(s)
- Javier Morante
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
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32
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Harzsch S, Hafner G. Evolution of eye development in arthropods: phylogenetic aspects. ARTHROPOD STRUCTURE & DEVELOPMENT 2006; 35:319-340. [PMID: 18089079 DOI: 10.1016/j.asd.2006.08.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 08/24/2006] [Indexed: 05/25/2023]
Abstract
The architecture of the adult arthropod visual system for many decades has contributed important character sets that are useful for reconstructing the phylogenetic relationships within this group. In the current paper we explore whether aspects of eye development can also contribute new arguments to the discussion of arthropod phylogeny. We review the current knowledge on eye formation in Trilobita, Xiphosura, Myriapoda, Hexapoda, and Crustacea. All euarthropod taxa share the motif of a proliferation zone at the side of the developing eye field that contributes new eye elements. Two major variations of this common motif can be distinguished: 1. The "row by row type" of Trilobita, Xiphosura, and Diplopoda. In this type, the proliferation zone at the side of the eye field generates new single, large elements with a high and variable cell number, which are added to the side of the eye and extend rows of existing eye elements. Cell proliferation, differentiation and ommatidial assembly seem to be separated in time but spatially confined within the precursors of the optic units which grow continuously once they are formed (intercalary growth). 2. The "morphogenetic front type" of eye formation in Crustacea+Hexapoda (Tetraconata). In this type, there is a clear temporal and spatial separation of the formation and differentiation processes. Proliferation and the initial steps of pattern formation take place in linear and parallel mitotic and morphogenetic fronts (the mitotic waves and the morphogenetic furrow/transition zone) and numerous but small new elements with a strictly fixed set of cells are added to the eye field. In Tetraconata, once formed, the individual ommatidia do not grow any more. Scutigeromorph chilopods take an intermediate position between these two major types. We suggest that the "row by row type" as seen in Trilobita, Xiphosura and Diplopoda represents the plesiomorphic developmental mode of eye formation from the euarthropod ground pattern whereas the "morphogenetic front type" is apomorphic for the Tetraconata. Our data are discussed with regard to two competing hypotheses on arthropod phylogeny, the "Tracheata" versus "Tetraconata" concept. The modes of eye development in Myriapoda is more parsimonious to explain in the Tetraconata hypothesis so that our data raise the possibility that myriapod eyes may not be secondarily reconstructed insect eyes as the prevailing hypothesis suggests.
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Affiliation(s)
- Steffen Harzsch
- Universität Ulm, Abteilung Neurobiologie and Sektion Biosystematische Dokumentation, Albert-Einstein-Str. 11, D-89081 Ulm, Germany
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