1
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Ellis KE, Bervoets S, Smihula H, Ganguly I, Vigato E, Auer TO, Benton R, Litwin-Kumar A, Caron SJC. Evolution of connectivity architecture in the Drosophila mushroom body. Nat Commun 2024; 15:4872. [PMID: 38849331 PMCID: PMC11161526 DOI: 10.1038/s41467-024-48839-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/14/2024] [Indexed: 06/09/2024] Open
Abstract
Brain evolution has primarily been studied at the macroscopic level by comparing the relative size of homologous brain centers between species. How neuronal circuits change at the cellular level over evolutionary time remains largely unanswered. Here, using a phylogenetically informed framework, we compare the olfactory circuits of three closely related Drosophila species that differ in their chemical ecology: the generalists Drosophila melanogaster and Drosophila simulans and Drosophila sechellia that specializes on ripe noni fruit. We examine a central part of the olfactory circuit that, to our knowledge, has not been investigated in these species-the connections between projection neurons and the Kenyon cells of the mushroom body-and identify species-specific connectivity patterns. We found that neurons encoding food odors connect more frequently with Kenyon cells, giving rise to species-specific biases in connectivity. These species-specific connectivity differences reflect two distinct neuronal phenotypes: in the number of projection neurons or in the number of presynaptic boutons formed by individual projection neurons. Finally, behavioral analyses suggest that such increased connectivity enhances learning performance in an associative task. Our study shows how fine-grained aspects of connectivity architecture in an associative brain center can change during evolution to reflect the chemical ecology of a species.
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Affiliation(s)
| | - Sven Bervoets
- School of Biological Sciences, University of Utah, Salt Lake City, USA
| | - Hayley Smihula
- School of Biological Sciences, University of Utah, Salt Lake City, USA
| | - Ishani Ganguly
- Center for Theoretical Neuroscience, Columbia University, New York, USA
| | - Eva Vigato
- School of Biological Sciences, University of Utah, Salt Lake City, USA
| | - Thomas O Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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2
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Wu Y, Wang Q, Yang W, Zhang S, Mao CX, He N, Zhou S, Zhou C, Liu W. The cluster digging behavior of larvae confers trophic benefits to fitness in insects. INSECT SCIENCE 2024; 31:870-884. [PMID: 38161191 DOI: 10.1111/1744-7917.13307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/20/2023] [Accepted: 10/30/2023] [Indexed: 01/03/2024]
Abstract
Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans. Fly larvae tend to cluster and form coordinated digging groups under crowded conditions, yet understanding the rules governing this behavior is in its infancy. We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior. Here, we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging. Subsequently, we investigated relative factors, including larval stage, population density, and food stiffness and quality, that affect the cluster digging behavior. Remarkably, oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters. More importantly, we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth, cross-section area, and food volume. We found that cluster digging behavior approximately increases 2.2 fold depth, 1.7-fold cross-section area, and 1.9 fold volume than control groups, respectively. Amplification of food sources significantly facilitates survival, larval development, and reproductive success of Drosophila challenged with competition for limited food resources, thereby conferring trophic benefits to fitness in insects. Overall, our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity, advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.
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Affiliation(s)
- Yujie Wu
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Qiang Wang
- School of Teacher Education, Nanjing Xiaozhuang University, Nanjing, China
| | - Weikang Yang
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
| | - Sheng Zhang
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
| | - Chuan-Xi Mao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of Life Science, Hubei University, Wuhan, China
| | - Nana He
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
| | - Shaojie Zhou
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
| | - Chuanming Zhou
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
| | - Wei Liu
- School of Plant Protection, Anhui Agricultural University; Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, Hefei, China
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3
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Farnworth MS, Montgomery SH. Evolution of neural circuitry and cognition. Biol Lett 2024; 20:20230576. [PMID: 38747685 DOI: 10.1098/rsbl.2023.0576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 03/26/2024] [Indexed: 05/25/2024] Open
Abstract
Neural circuits govern the interface between the external environment, internal cues and outwardly directed behaviours. To process multiple environmental stimuli and integrate these with internal state requires considerable neural computation. Expansion in neural network size, most readily represented by whole brain size, has historically been linked to behavioural complexity, or the predominance of cognitive behaviours. Yet, it is largely unclear which aspects of circuit variation impact variation in performance. A key question in the field of evolutionary neurobiology is therefore how neural circuits evolve to allow improved behavioural performance or innovation. We discuss this question by first exploring how volumetric changes in brain areas reflect actual neural circuit change. We explore three major axes of neural circuit evolution-replication, restructuring and reconditioning of cells and circuits-and discuss how these could relate to broader phenotypes and behavioural variation. This discussion touches on the relevant uses and limitations of volumetrics, while advocating a more circuit-based view of cognition. We then use this framework to showcase an example from the insect brain, the multi-sensory integration and internal processing that is shared between the mushroom bodies and central complex. We end by identifying future trends in this research area, which promise to advance the field of evolutionary neurobiology.
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Affiliation(s)
- Max S Farnworth
- School of Biological Sciences, University of Bristol , Bristol, UK
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4
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Rode NO, Meslin C. A sweet tooth makes a fly a pest. Trends Ecol Evol 2024; 39:315-317. [PMID: 38493056 DOI: 10.1016/j.tree.2024.03.002] [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: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/18/2024]
Abstract
The major insect pest of soft and stone fruits, the spotted-wing drosophila, Drosophila suzukii, has evolved a greater preference for laying eggs on ripe fruits over fermented ones. In a recent study, Cavey et al. found that higher responsiveness to low sugar concentrations has had an important role in this evolutionary shift in egg-laying behavior.
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Affiliation(s)
- Nicolas O Rode
- CBGP, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France.
| | - Camille Meslin
- Sorbonne Université, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Institut de Recherche pour le Développement, Université Paris-Est-Créteil-Val-de-Marne, Université Paris Cité, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Versailles, France.
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5
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Cavigliasso F, Savitsky M, Koval A, Erkosar B, Savary L, Gallart-Ayala H, Ivanisevic J, Katanaev VL, Kawecki TJ. Cis-regulatory polymorphism at fiz ecdysone oxidase contributes to polygenic evolutionary response to malnutrition in Drosophila. PLoS Genet 2024; 20:e1011204. [PMID: 38452112 PMCID: PMC10962836 DOI: 10.1371/journal.pgen.1011204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 03/25/2024] [Accepted: 02/29/2024] [Indexed: 03/09/2024] Open
Abstract
We investigate the contribution of a candidate gene, fiz (fezzik), to complex polygenic adaptation to juvenile malnutrition in Drosophila melanogaster. Experimental populations maintained for >250 generations of experimental evolution to a nutritionally poor larval diet (Selected populations) evolved several-fold lower fiz expression compared to unselected Control populations. Here we show that this divergence in fiz expression is mediated by a cis-regulatory polymorphism. This polymorphism, originally sampled from a natural population in Switzerland, is distinct from a second cis-regulatory SNP previously identified in non-African D. melanogaster populations, implying that two independent cis-regulatory variants promoting high fiz expression segregate in non-African populations. Enzymatic analyses of Fiz protein expressed in E. coli demonstrate that it has ecdysone oxidase activity acting on both ecdysone and 20-hydroxyecdysone. Four of five fiz paralogs annotated to ecdysteroid metabolism also show reduced expression in Selected larvae, implying that malnutrition-driven selection favored general downregulation of ecdysone oxidases. Finally, as an independent test of the role of fiz in poor diet adaptation, we show that fiz knockdown by RNAi results in faster larval growth on the poor diet, but at the cost of greatly reduced survival. These results imply that downregulation of fiz in Selected populations was favored by selection on the nutritionally poor diet because of its role in suppressing growth in response to nutrient shortage. However, they suggest that fiz downregulation is only adaptive in combination with other changes evolved by Selected populations, which ensure that the organism can sustain the faster growth promoted by fiz downregulation.
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Affiliation(s)
- Fanny Cavigliasso
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Mikhail Savitsky
- HumanaFly Facility, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Alexey Koval
- Translational Research Centre in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Berra Erkosar
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Loriane Savary
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Hector Gallart-Ayala
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Julijana Ivanisevic
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Vladimir L. Katanaev
- Translational Research Centre in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Tadeusz J. Kawecki
- Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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6
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Sullivan LF, Barker MS, Felix PC, Vuong RQ, White BH. Neuromodulation and the toolkit for behavioural evolution: can ecdysis shed light on an old problem? FEBS J 2024; 291:1049-1079. [PMID: 36223183 PMCID: PMC10166064 DOI: 10.1111/febs.16650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/06/2022] [Accepted: 10/12/2022] [Indexed: 05/10/2023]
Abstract
The geneticist Thomas Dobzhansky famously declared: 'Nothing in biology makes sense except in the light of evolution'. A key evolutionary adaptation of Metazoa is directed movement, which has been elaborated into a spectacularly varied number of behaviours in animal clades. The mechanisms by which animal behaviours have evolved, however, remain unresolved. This is due, in part, to the indirect control of behaviour by the genome, which provides the components for both building and operating the brain circuits that generate behaviour. These brain circuits are adapted to respond flexibly to environmental contingencies and physiological needs and can change as a function of experience. The resulting plasticity of behavioural expression makes it difficult to characterize homologous elements of behaviour and to track their evolution. Here, we evaluate progress in identifying the genetic substrates of behavioural evolution and suggest that examining adaptive changes in neuromodulatory signalling may be a particularly productive focus for future studies. We propose that the behavioural sequences used by ecdysozoans to moult are an attractive model for studying the role of neuromodulation in behavioural evolution.
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Affiliation(s)
- Luis F Sullivan
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Matthew S Barker
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Princess C Felix
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Richard Q Vuong
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Benjamin H White
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
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7
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Takagi S, Sancer G, Abuin L, Stupski SD, Arguello JR, Prieto-Godino LL, Stern DL, Cruchet S, Alvarez-Ocana R, Wienecke CFR, van Breugel F, Jeanne JM, Auer TO, Benton R. Sensory neuron population expansion enhances odor tracking without sensitizing projection neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.15.556782. [PMID: 37745467 PMCID: PMC10515935 DOI: 10.1101/2023.09.15.556782] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The evolutionary expansion of sensory neuron populations detecting important environmental cues is widespread, but functionally enigmatic. We investigated this phenomenon through comparison of homologous neural pathways of Drosophila melanogaster and its close relative Drosophila sechellia , an extreme specialist for Morinda citrifolia noni fruit. D. sechellia has evolved species-specific expansions in select, noni-detecting olfactory sensory neuron (OSN) populations, through multigenic changes. Activation and inhibition of defined proportions of neurons demonstrate that OSN population increases contribute to stronger, more persistent, noni-odor tracking behavior. These sensory neuron expansions result in increased synaptic connections with their projection neuron (PN) partners, which are conserved in number between species. Surprisingly, having more OSNs does not lead to greater odor-evoked PN sensitivity or reliability. Rather, pathways with increased sensory pooling exhibit reduced PN adaptation, likely through weakened lateral inhibition. Our work reveals an unexpected functional impact of sensory neuron expansions to explain ecologically-relevant, species-specific behavior.
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8
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Ding SS, Fox JL, Gordus A, Joshi A, Liao JC, Scholz M. Fantastic beasts and how to study them: rethinking experimental animal behavior. J Exp Biol 2024; 227:jeb247003. [PMID: 38372042 PMCID: PMC10911175 DOI: 10.1242/jeb.247003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Humans have been trying to understand animal behavior at least since recorded history. Recent rapid development of new technologies has allowed us to make significant progress in understanding the physiological and molecular mechanisms underlying behavior, a key goal of neuroethology. However, there is a tradeoff when studying animal behavior and its underlying biological mechanisms: common behavior protocols in the laboratory are designed to be replicable and controlled, but they often fail to encompass the variability and breadth of natural behavior. This Commentary proposes a framework of 10 key questions that aim to guide researchers in incorporating a rich natural context into their experimental design or in choosing a new animal study system. The 10 questions cover overarching experimental considerations that can provide a template for interspecies comparisons, enable us to develop studies in new model organisms and unlock new experiments in our quest to understand behavior.
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Affiliation(s)
- Siyu Serena Ding
- Max Planck Institute of Animal Behavior, 78464 Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
| | - Jessica L. Fox
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrew Gordus
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Abhilasha Joshi
- Departments of Physiology and Psychiatry, University of California, San Francisco, CA 94158, USA
| | - James C. Liao
- Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesar, 53175 Bonn, Germany
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9
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Bontonou G, Saint-Leandre B, Kafle T, Baticle T, Hassan A, Sánchez-Alcañiz JA, Arguello JR. Evolution of chemosensory tissues and cells across ecologically diverse Drosophilids. Nat Commun 2024; 15:1047. [PMID: 38316749 PMCID: PMC10844241 DOI: 10.1038/s41467-023-44558-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/19/2023] [Indexed: 02/07/2024] Open
Abstract
Chemosensory tissues exhibit significant between-species variability, yet the evolution of gene expression and cell types underlying this diversity remain poorly understood. To address these questions, we conducted transcriptomic analyses of five chemosensory tissues from six Drosophila species and integrated the findings with single-cell datasets. While stabilizing selection predominantly shapes chemosensory transcriptomes, thousands of genes in each tissue have evolved expression differences. Genes that have changed expression in one tissue have often changed in multiple other tissues but at different past epochs and are more likely to be cell type-specific than unchanged genes. Notably, chemosensory-related genes have undergone widespread expression changes, with numerous species-specific gains/losses including novel chemoreceptors expression patterns. Sex differences are also pervasive, including a D. melanogaster-specific excess of male-biased expression in sensory and muscle cells in its forelegs. Together, our analyses provide new insights for understanding evolutionary changes in chemosensory tissues at both global and individual gene levels.
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Affiliation(s)
- Gwénaëlle Bontonou
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
| | - Bastien Saint-Leandre
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
| | - Tane Kafle
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Tess Baticle
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Afrah Hassan
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | | | - J Roman Arguello
- Department of Ecology & Evolution, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK.
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10
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Ellis KE, Domagala DM, Caron SJC. Mapping Kenyon cell inputs in Drosophila using dye electroporation. STAR Protoc 2023; 4:102478. [PMID: 37864788 PMCID: PMC10616406 DOI: 10.1016/j.xpro.2023.102478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/31/2023] [Accepted: 06/30/2023] [Indexed: 10/23/2023] Open
Abstract
Here, we describe a technique for charting the inputs of individual Kenyon cells in the Drosophila brain. In this technique, a single Kenyon cell per brain hemisphere is photo-labeled to visualize its claw-like dendritic terminals; a dye-filled electrode is used to backfill the projection neuron connected to each claw. This process can be repeated in hundreds of brains to build a connectivity matrix. Statistical analyses of such a matrix can reveal connectivity patterns such as random input and biased connectivity. For complete details on the use and execution of this protocol, please refer to Hayashi et al. (2022).1.
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Affiliation(s)
| | - Drue Marie Domagala
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
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11
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Depetris-Chauvin A, Galagovsky D, Keesey IW, Hansson BS, Sachse S, Knaden M. Evolution at multiple processing levels underlies odor-guided behavior in the genus Drosophila. Curr Biol 2023; 33:4771-4785.e7. [PMID: 37804828 DOI: 10.1016/j.cub.2023.09.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/02/2023] [Accepted: 09/15/2023] [Indexed: 10/09/2023]
Abstract
Olfaction is a fundamental sense guiding animals to their food. How the olfactory system evolves and influences behavior is still poorly understood. Here, we selected five drosophilid species, including Drosophila melanogaster, inhabiting different ecological niches to compare their olfactory systems at multiple levels. We first identified ecologically relevant natural food odorants from every species and established species-specific odorant preferences. To compare odor coding in sensory neurons, we analyzed the antennal lobe (AL) structure, generated glomerular atlases, and developed GCaMP transgenic lines for all species. Although subsets of glomeruli showed distinct tuning profiles, odorants inducing species-specific preferences were coded generally similarly. Species distantly related or occupying different habitats showed more evident differences in odor coding, and further analysis revealed that changes in olfactory receptor (OR) sequences partially explain these differences. Our results demonstrate that genetic distance in phylogeny and ecological niche occupancy are key determinants in the evolution of ORs, AL structures, odor coding, and behavior. Interestingly, changes in odor coding among species could not be explained by evolutionary changes at a single olfactory processing level but rather are a complex phenomenon based on changes at multiple levels.
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Affiliation(s)
- Ana Depetris-Chauvin
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany; Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Diego Galagovsky
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Ian W Keesey
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
| | - Markus Knaden
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, 07745 Jena, Germany.
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12
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Dey M, Brown E, Charlu S, Keene A, Dahanukar A. Evolution of fatty acid taste in drosophilids. Cell Rep 2023; 42:113297. [PMID: 37864792 PMCID: PMC10697176 DOI: 10.1016/j.celrep.2023.113297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 09/01/2023] [Accepted: 10/02/2023] [Indexed: 10/23/2023] Open
Abstract
Comparative studies of related but ecologically distinct species can reveal how the nervous system evolves to drive behaviors that are particularly suited to certain environments. Drosophila melanogaster is a generalist that feeds and oviposits on most overripe fruits. A sibling species, D. sechellia, is an obligate specialist of Morinda citrifolia (noni) fruit, which is rich in fatty acids (FAs). To understand evolution of noni taste preference, we characterized behavioral and cellular responses to noni-associated FAs in three related drosophilids. We find that mixtures of sugar and noni FAs evoke strong aversion in the generalist species but not in D. sechellia. Surveys of taste sensory responses reveal noni FA- and species-specific differences in at least two mechanisms-bitter neuron activation and sweet neuron inhibition-that correlate with shifts in noni preference. Chemoreceptor mutant analysis in D. melanogaster predicts that multiple genetic changes account for evolution of gustatory preference in D. sechellia.
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Affiliation(s)
- Manali Dey
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Elizabeth Brown
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Sandhya Charlu
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Alex Keene
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA; Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA; Department of Molecular, Cell & Systems Biology, University of California, Riverside, Riverside, CA 92521, USA.
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13
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Ellis KE, Bervoets S, Smihula H, Ganguly I, Vigato E, Auer TO, Benton R, Litwin-Kumar A, Caron SJC. Evolution of connectivity architecture in the Drosophila mushroom body. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.10.528036. [PMID: 36798335 PMCID: PMC9934700 DOI: 10.1101/2023.02.10.528036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Brain evolution has primarily been studied at the macroscopic level by comparing the relative size of homologous brain centers between species. How neuronal circuits change at the cellular level over evolutionary time remains largely unanswered. Here, using a phylogenetically informed framework, we compare the olfactory circuits of three closely related Drosophila species that differ radically in their chemical ecology: the generalists Drosophila melanogaster and Drosophila simulans that feed on fermenting fruit, and Drosophila sechellia that specializes on ripe noni fruit. We examine a central part of the olfactory circuit that has not yet been investigated in these species - the connections between the projection neurons of the antennal lobe and the Kenyon cells of the mushroom body, an associative brain center - to identify species-specific connectivity patterns. We found that neurons encoding food odors - the DC3 neurons in D. melanogaster and D. simulans and the DL2d neurons in D. sechellia - connect more frequently with Kenyon cells, giving rise to species-specific biases in connectivity. These species-specific differences in connectivity reflect two distinct neuronal phenotypes: in the number of projection neurons or in the number of presynaptic boutons formed by individual projection neurons. Finally, behavioral analyses suggest that such increased connectivity enhances learning performance in an associative task. Our study shows how fine-grained aspects of connectivity architecture in an associative brain center can change during evolution to reflect the chemical ecology of a species.
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14
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Zhu J, Boivin JC, Pang S, Xu CS, Lu Z, Saalfeld S, Hess HF, Ohyama T. Comparative connectomics and escape behavior in larvae of closely related Drosophila species. Curr Biol 2023:S0960-9822(23)00675-9. [PMID: 37285846 DOI: 10.1016/j.cub.2023.05.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 05/02/2023] [Accepted: 05/17/2023] [Indexed: 06/09/2023]
Abstract
Evolution has generated an enormous variety of morphological, physiological, and behavioral traits in animals. How do behaviors evolve in different directions in species equipped with similar neurons and molecular components? Here we adopted a comparative approach to investigate the similarities and differences of escape behaviors in response to noxious stimuli and their underlying neural circuits between closely related drosophilid species. Drosophilids show a wide range of escape behaviors in response to noxious cues, including escape crawling, stopping, head casting, and rolling. Here we find that D. santomea, compared with its close relative D. melanogaster, shows a higher probability of rolling in response to noxious stimulation. To assess whether this behavioral difference could be attributed to differences in neural circuitry, we generated focused ion beam-scanning electron microscope volumes of the ventral nerve cord of D. santomea to reconstruct the downstream partners of mdIV, a nociceptive sensory neuron in D. melanogaster. Along with partner interneurons of mdVI (including Basin-2, a multisensory integration neuron necessary for rolling) previously identified in D. melanogaster, we identified two additional partners of mdVI in D. santomea. Finally, we showed that joint activation of one of the partners (Basin-1) and a common partner (Basin-2) in D. melanogaster increased rolling probability, suggesting that the high rolling probability in D. santomea is mediated by the additional activation of Basin-1 by mdIV. These results provide a plausible mechanistic explanation for how closely related species exhibit quantitative differences in the likelihood of expressing the same behavior.
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Affiliation(s)
- Jiayi Zhu
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Integrated Program of Neuroscience, McGill University, Pine Avenue W., Montreal, QC H3A 1A1, Canada
| | - Jean-Christophe Boivin
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Integrated Program of Neuroscience, McGill University, Pine Avenue W., Montreal, QC H3A 1A1, Canada
| | - Song Pang
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Zhiyuan Lu
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Tomoko Ohyama
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Alan Edwards Center for Research on Pain, McGill University, University Street, Montreal, QC H3A 2B4, Canada.
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15
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Álvarez-Ocaña R, Shahandeh MP, Ray V, Auer TO, Gompel N, Benton R. Odor-regulated oviposition behavior in an ecological specialist. Nat Commun 2023; 14:3041. [PMID: 37236992 DOI: 10.1038/s41467-023-38722-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Colonization of a novel ecological niche can require, or be driven by, evolution of an animal's behaviors promoting their reproductive success. We investigated the evolution and sensory basis of oviposition in Drosophila sechellia, a close relative of Drosophila melanogaster that exhibits extreme specialism for Morinda citrifolia noni fruit. D. sechellia produces fewer eggs than other drosophilids and lays these almost exclusively on noni substrates. We show that visual, textural and social cues do not explain this species-specific preference. By contrast, we find that loss of olfactory input in D. sechellia, but not D. melanogaster, essentially abolishes egg-laying, suggesting that olfaction gates gustatory-driven noni preference. Noni odors are detected by redundant olfactory pathways, but we discover a role for hexanoic acid and the cognate Ionotropic receptor 75b (Ir75b) in odor-evoked oviposition. Through receptor exchange in D. melanogaster, we provide evidence for a causal contribution of odor-tuning changes in Ir75b to the evolution of D. sechellia's oviposition behavior.
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Affiliation(s)
- Raquel Álvarez-Ocaña
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Michael P Shahandeh
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Vijayaditya Ray
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152, Planegg-Martinsried, Germany
| | - Thomas O Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Nicolas Gompel
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152, Planegg-Martinsried, Germany
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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16
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Ribeiro LB, Proença CEB, Tidon R. Host Preferences Shown by Drosophilids (Diptera) in a Commercial Fruit and Vegetable Distribution Center Follow the Wild Neotropical Pattern. INSECTS 2023; 14:375. [PMID: 37103190 PMCID: PMC10141734 DOI: 10.3390/insects14040375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/04/2023] [Accepted: 04/08/2023] [Indexed: 06/19/2023]
Abstract
Although drosophilids have been extensively studied in laboratories worldwide, their ecology is still relatively poorly understood. This is unfortunate because some species are currently expanding their geographic distribution and infesting fruit crops. Here, we investigated the relationship between drosophilids and potential plant hosts in a commercial fruit and vegetable distribution center in the Neotropical region. We collected discarded fruits and vegetables from this commercial center during two time periods (2007-2008 and 2017-2018). Resources were weighted and individually monitored in the laboratory. The drosophilids that emerged were identified, and the relationship between them and their resources was explored. From the 99,478 kg of potential hosts collected, we identified 48 plant taxa, from which 48,894 drosophilids of 16 species emerged. On both collecting occasions, drosophilid assemblages were strongly dominated by basically the same exotic species, which explore a broader range of resources, especially those of exotic origin, when compared to neotropical drosophilids. These results are concerning because the studied site, Along with other urban markets around the world, might be acting as sources of generalist widespread species that disperse to surrounding natural vegetation and contribute to biotic homogenization.
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Affiliation(s)
- Laís Barbosa Ribeiro
- Graduate Program in Ecology, Institute of Biological Sciences, University of Brasilia, Brasilia 70910-900, Brazil;
| | | | - Rosana Tidon
- Graduate Program in Ecology, Institute of Biological Sciences, University of Brasilia, Brasilia 70910-900, Brazil;
- Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasília, Brasilia 70910-900, Brazil
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17
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Reisenman CE, Wong J, Vedagarbha N, Livelo C, Scott K. Taste adaptations associated with host specialization in the specialist Drosophila sechellia. J Exp Biol 2023; 226:jeb244641. [PMID: 36637369 PMCID: PMC10088416 DOI: 10.1242/jeb.244641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 01/09/2023] [Indexed: 01/14/2023]
Abstract
Chemosensory-driven host plant specialization is a major force mediating insect ecological adaptation and speciation. Drosophila sechellia, a species endemic to the Seychelles islands, feeds and oviposits on Morinda citrifolia almost exclusively. This fruit is harmless to D. sechellia but toxic to other Drosophilidae, including the closely related generalists D. simulans and D. melanogaster, because of its high content of fatty acids. While several olfactory adaptations mediating D. sechellia's preference for its host have been uncovered, the role of taste has been much less examined. We found that D. sechellia has reduced taste and feeding aversion to bitter compounds and host fatty acids that are aversive to D. melanogaster and D. simulans. The loss of aversion to canavanine, coumarin and fatty acids arose in the D. sechellia lineage, as its sister species D. simulans showed responses akin to those of D. melanogaster. Drosophila sechellia has increased taste and feeding responses towards M. citrifolia. These results are in line with D. sechellia's loss of genes that encode bitter gustatory receptors (GRs) in D. melanogaster. We found that two GR genes which are lost in D. sechellia, GR39a.a and GR28b.a, influence the reduction of aversive responses to some bitter compounds. Also, D. sechellia has increased appetite for a prominent host fatty acid compound that is toxic to its relatives. Our results support the hypothesis that changes in the taste system, specifically a reduction of sensitivity to bitter compounds that deter generalist ancestors, contribute to the specialization of D. sechellia for its host.
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Affiliation(s)
- Carolina E. Reisenman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Essig Museum of Entomology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Joshua Wong
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Namrata Vedagarbha
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | | | - Kristin Scott
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
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18
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Abstract
Among the many wonders of nature, the sense of smell of the fly Drosophila melanogaster might seem, at first glance, of esoteric interest. Nevertheless, for over a century, the 'nose' of this insect has been an extraordinary system to explore questions in animal behaviour, ecology and evolution, neuroscience, physiology and molecular genetics. The insights gained are relevant for our understanding of the sensory biology of vertebrates, including humans, and other insect species, encompassing those detrimental to human health. Here, I present an overview of our current knowledge of D. melanogaster olfaction, from molecules to behaviours, with an emphasis on the historical motivations of studies and illustration of how technical innovations have enabled advances. I also highlight some of the pressing and long-term questions.
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Affiliation(s)
- Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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19
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Scalzotto M, Ng R, Cruchet S, Saina M, Armida J, Su CY, Benton R. Pheromone sensing in Drosophila requires support cell-expressed Osiris 8. BMC Biol 2022; 20:230. [PMID: 36217142 PMCID: PMC9552441 DOI: 10.1186/s12915-022-01425-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background The nose of most animals comprises multiple sensory subsystems, which are defined by the expression of different olfactory receptor families. Drosophila melanogaster antennae contain two morphologically and functionally distinct subsystems that express odorant receptors (Ors) or ionotropic receptors (Irs). Although these receptors have been thoroughly characterized in this species, the subsystem-specific expression and roles of other genes are much less well-understood. Results Here we generate subsystem-specific transcriptomic datasets to identify hundreds of genes, encoding diverse protein classes, that are selectively enriched in either Or or Ir subsystems. Using single-cell antennal transcriptomic data and RNA in situ hybridization, we find that most neuronal genes—other than sensory receptor genes—are broadly expressed within the subsystems. By contrast, we identify many non-neuronal genes that exhibit highly selective expression, revealing substantial molecular heterogeneity in the non-neuronal cellular components of the olfactory subsystems. We characterize one Or subsystem-specific non-neuronal molecule, Osiris 8 (Osi8), a conserved member of a large, insect-specific family of transmembrane proteins. Osi8 is expressed in the membranes of tormogen support cells of pheromone-sensing trichoid sensilla. Loss of Osi8 does not have obvious impact on trichoid sensillar development or basal neuronal activity, but abolishes high sensitivity responses to pheromone ligands. Conclusions This work identifies a new protein required for insect pheromone detection, emphasizes the importance of support cells in neuronal sensory functions, and provides a resource for future characterization of other olfactory subsystem-specific genes. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01425-w.
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Affiliation(s)
- Marta Scalzotto
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Steeve Cruchet
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Michael Saina
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Jan Armida
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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20
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Rondón JJ, Moreyra NN, Pisarenco VA, Rozas J, Hurtado J, Hasson E. Evolution of the odorant-binding protein gene family in Drosophila. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.957247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Odorant-binding proteins (OBPs) are encoded by a gene family involved in the perception of olfactory signals in insects. This chemosensory gene family has been advocated as a candidate to mediate host preference and host shifts in insects, although it also participates in other physiological processes. Remarkable differences in the OBP gene repertoire have been described across insect groups, suggesting an accelerated gene turnover rate. The genus Drosophila, is a valuable resource for ecological genomics studies since it comprises groups of ecologically diverse species and there are genome data for many of them. Here, we investigate the molecular evolution of this chemosensory gene family across 19 Drosophila genomes, including the melanogaster and repleta species groups, which are mostly associated with rotting fruit and cacti, respectively. We also compared the OBP repertoire among the closely related species of the repleta group, associated with different subfamilies of Cactaceae that represent disparate chemical challenges for the flies. We found that the gene family size varies widely between species, ranging from 39 to 54 candidate OBPs. Indeed, more than 54% of these genes are organized in clusters and located on chromosomes X, 2, and 5, with a distribution conserved throughout the genus. The family sizes in the repleta group and D. virilis (virilis-repleta radiation) were smaller than in the melanogaster group. We tested alternative evolutionary models for OBP family size and turnover rates based on different ecological scenarios. We found heterogeneous gene turnover rates (GR) in comparisons involving columnar cactus specialists, prickly pear specialists, and fruit dwellers lineages, and signals of rapid molecular evolution compatible with positive selection in specific OBP genes. Taking ours and previous results together, we propose that this chemosensory gene family is involved in host adaptation and hypothesize that the adoption of the cactophilic lifestyle in the repleta group accelerated the evolution of members of the family.
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21
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Copy number changes in co-expressed odorant receptor genes enable selection for sensory differences in drosophilid species. Nat Ecol Evol 2022; 6:1343-1353. [PMID: 35864227 DOI: 10.1038/s41559-022-01830-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 06/15/2022] [Indexed: 11/09/2022]
Abstract
Despite numerous examples of chemoreceptor gene family expansions and contractions, how these relate to modifications in the sensory neuron populations in which they are expressed remains unclear. Drosophila melanogaster's odorant receptor (Or) family is ideal for addressing this question because most Ors are expressed in distinct olfactory sensory neuron (OSN) types. Between-species changes in Or copy number may therefore indicate increases or reductions in the number of OSN populations. Here we investigated the Or67a subfamily, which exhibits copy number variation in D. melanogaster and its closest relatives: D. simulans, D. sechellia and D. mauritiana. These species' common ancestor had three Or67a paralogues that had already diverged adaptively. Following speciation, two Or67a paralogues were lost independently in D. melanogaster and D. sechellia, with ongoing positive selection shaping the intact genes. Unexpectedly, the functionally diverged Or67a paralogues in D. simulans are co-expressed in a single neuron population, which projects to a glomerulus homologous to that innervated by Or67a neurons in D. melanogaster. Thus, while sensory pathway neuroanatomy is conserved, independent selection on co-expressed receptors has contributed to species-specific peripheral coding. This work reveals a type of adaptive change largely overlooked for olfactory evolution, raising the possibility that similar processes influence other cases of insect Or co-expression.
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