1
|
Fanara JJ, Beti MIL, Gandini L, Hasson E. Oviposition behaviour in Drosophila melanogaster: Genetic and behavioural decoupling between oviposition acceptance and preference for natural fruits. J Evol Biol 2023; 36:251-263. [PMID: 36357966 DOI: 10.1111/jeb.14109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 11/12/2022]
Abstract
In phytophagous insects, oviposition behaviour is an important component of habitat selection and, given the multiplicity of genetic and environmental factors affecting its expression, is defined as a complex character resulting from the sum of interdependent traits. Here, we study two components of egg-laying behaviour: oviposition acceptance (OA) and oviposition preference (OP) in Drosophila melanogaster using three natural fruits as resources (grape, tomato and orange) by means of no-choice and two-choice experiments, respectively. This experimental design allowed us to show that the results obtained in two-choice assays (OP) cannot be accounted for by those resulting from no-choice assays (OA). Since the genomes of all lines used are completely sequenced, we perform a genome-wide association study to identify and characterize the genetic underpinnings of these oviposition behaviour traits. The analyses revealed different candidate genes affecting natural genetic variation of both OA and OP traits. Moreover, our results suggest behavioural and genetic decoupling between OA and OP and that egg-laying behaviour is plastic and context-dependent. Such independence in the genetic architectures of OA and OP variation may influence different aspects of oviposition behaviour, including plasticity, canalization, host shift and maintenance of genetic variability, which contributes to the adoption of adaptive strategies during habitat selection.
Collapse
Affiliation(s)
- Juan J Fanara
- Laboratorio de Evolución, Departamento de Ecología, Genética y Evolución, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina.,Laboratorio de Evolución, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET-UBA, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina
| | - Maria I L Beti
- Laboratorio de Evolución, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET-UBA, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina
| | - Luciano Gandini
- Laboratorio de Evolución, Departamento de Ecología, Genética y Evolución, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina
| | - Esteban Hasson
- Laboratorio de Evolución, Departamento de Ecología, Genética y Evolución, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina.,Laboratorio de Evolución, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET-UBA, FCEN, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, Buenos Aires, Argentina
| |
Collapse
|
2
|
Elias R, Talyn B, Melchiorre E. Dietary Behavior of Drosophila melanogaster Fed with Genetically-Modified Corn or Roundup ®. J Xenobiot 2021; 11:215-227. [PMID: 34940514 PMCID: PMC8703958 DOI: 10.3390/jox11040014] [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: 10/29/2020] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/03/2022] Open
Abstract
With the rise in concern about GMOs and pesticides on human health, we have utilized Drosophila melanogaster as a model organism for understanding the effects of Roundup-Ready® GMO diets on health. We recorded dietary behavior during and after exposure to a medium containing GMO or non-GMO corn, Roundup® in organic corn medium, and sucrose with or without one of the two Roundup® formulations. No differences in behavior were observed when Drosophila were exposed to a medium containing Roundup-Ready® GMO or non-GMO corn. Drosophila can detect and refrain from eating sucrose containing one Roundup® formulation, Ready-to-Use, which contains pelargonic acid in addition to glyphosate as an active ingredient. Drosophila exhibited dose-dependent increased consumption of sucrose alone after exposure to a medium containing either Roundup® formulation. This may indicate that flies eating a medium with Roundup® eat less and were thus hungrier when then given sucrose solution; that a medium with Roundup® is more difficult to digest; or that a medium with Roundup® is less nutritious, as would be the case if nutritionally important microbes grew on control medium, but not one containing Roundup®.
Collapse
Affiliation(s)
- Raquel Elias
- Department of Biology, California State University, San Bernardino, CA 92407, USA;
| | - Becky Talyn
- College of Natural Sciences, California State University, San Bernardino, CA 92407, USA
- Correspondence: ; Tel.: +1-909-537-5303
| | - Erik Melchiorre
- Department of Geology, California State University, San Bernardino, CA 92407, USA;
| |
Collapse
|
3
|
Toshima N, Schleyer M. Neuronal processing of amino acids in Drosophila: from taste sensing to behavioural regulation. CURRENT OPINION IN INSECT SCIENCE 2019; 36:39-44. [PMID: 31473590 DOI: 10.1016/j.cois.2019.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/19/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Finding and feeding on appropriate food are crucial for all animals. Carbohydrates and amino acids are both essential nutrients, albeit with distinct roles: the former are the main energy source whereas the latter are the building blocks of proteins and are used as neurotransmitters. Despite their crucial role, neither the sensing nor the neuronal processing of amino acids is well understood. Studies in Drosophila melanogaster have only recently gained momentum in shedding new light on the molecular and neuronal mechanisms of peripheral and internal amino acid sensing, as well as the organization of amino acid feeding behaviour. Furthermore, amino acids have been shown to act as rewards in associative learning. Focusing on recent studies in Drosophila, we summarize what is known so far about the perception of, and the behavioural responses to, amino acids in insects, and try to identify key questions for future research.
Collapse
Affiliation(s)
- Naoko Toshima
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology (LIN), Brenneckestrasse 6, 39118 Magdeburg, Germany.
| | - Michael Schleyer
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology (LIN), Brenneckestrasse 6, 39118 Magdeburg, Germany
| |
Collapse
|
4
|
Yang Z, Huang R, Fu X, Wang G, Qi W, Mao D, Shi Z, Shen WL, Wang L. A post-ingestive amino acid sensor promotes food consumption in Drosophila. Cell Res 2018; 28:1013-1025. [PMID: 30209352 PMCID: PMC6170445 DOI: 10.1038/s41422-018-0084-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/19/2018] [Accepted: 08/13/2018] [Indexed: 11/29/2022] Open
Abstract
Adequate protein intake is crucial for the survival and well-being of animals. How animals assess prospective protein sources and ensure dietary amino acid intake plays a critical role in protein homeostasis. By using a quantitative feeding assay, we show that three amino acids, L-glutamate (L-Glu), L-alanine (L-Ala) and L-aspartate (L-Asp), but not their D-enantiomers or the other 17 natural L-amino acids combined, rapidly promote food consumption in the fruit fly Drosophila melanogaster. This feeding-promoting effect of dietary amino acids is independent of mating experience and internal nutritional status. In vivo and ex vivo calcium imagings show that six brain neurons expressing diuretic hormone 44 (DH44) can be rapidly and directly activated by these amino acids, suggesting that these neurons are an amino acid sensor. Genetic inactivation of DH44+ neurons abolishes the increase in food consumption induced by dietary amino acids, whereas genetic activation of these neurons is sufficient to promote feeding, suggesting that DH44+ neurons mediate the effect of dietary amino acids to promote food consumption. Single-cell transcriptome analysis and immunostaining reveal that a putative amino acid transporter, CG13248, is enriched in DH44+ neurons. Knocking down CG13248 expression in DH44+ neurons blocks the increase in food consumption and eliminates calcium responses induced by dietary amino acids. Therefore, these data identify DH44+ neuron as a key sensor to detect amino acids and to enhance food intake via a putative transporter CG13248. These results shed critical light on the regulation of protein homeostasis at organismal levels by the nervous system.
Collapse
Affiliation(s)
- Zhe Yang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China.,Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Rui Huang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College, Chongqing University, Chongqing, 400030, China.,Medical School, Chongqing University, 400030, China
| | - Xin Fu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gaohang Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China.,Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Wei Qi
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China.,Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Decai Mao
- Gene Regulatory Laboratory, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Zhaomei Shi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Wei L Shen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Liming Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, 310058, Zhejiang, China. .,Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, 310058, Zhejiang, China.
| |
Collapse
|
5
|
Hughson BN, Anreiter I, Jackson Chornenki NL, Murphy KR, Ja WW, Huber R, Sokolowski MB. The adult foraging assay (AFA) detects strain and food-deprivation effects in feeding-related traits of Drosophila melanogaster. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:20-29. [PMID: 28860037 PMCID: PMC5832525 DOI: 10.1016/j.jinsphys.2017.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/23/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
We introduce a high-resolution adult foraging assay (AFA) that relates pre- and post-ingestive walking behavior to individual instances of food consumption. We explore the utility of the AFA by taking advantage of established rover and sitter strains known to differ in a number of feeding-related traits. The AFA allows us to effectively distinguish locomotor behavior in Fed and Food-Deprived (FD) rover and sitter foragers. We found that rovers exhibit more exploratory behavior into the center of an arena containing sucrose drops compared to sitters who hug the edges of the arena and exhibit thigmotaxic behavior. Rovers also discover and ingest more sucrose drops than sitters. Sitters become more exploratory with increasing durations of food deprivation and the number of ingestion events also increases progressively with prolonged fasting for both strains. AFA results are matched by strain differences in sucrose responsiveness, starvation resistance, and lipid levels, suggesting that under the same feeding condition, rovers are more motivated to forage than sitters. These findings demonstrate the AFA's ability to effectively discriminate movement and food ingestion patterns of different strains and feeding treatments.
Collapse
Affiliation(s)
- Bryon N Hughson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Ina Anreiter
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada; Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St. West, Suite 1400, Toronto, Ontario M5G 1Z8, Canada
| | - Nicholas L Jackson Chornenki
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Keith R Murphy
- Program in Integrative Biology and Neuroscience, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way 3B3, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, 130 Scripps Way 3B3, Jupiter, FL 33458, USA
| | - William W Ja
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way 3B3, Jupiter, FL 33458, USA; Center on Aging, The Scripps Research Institute, 130 Scripps Way 3B3, Jupiter, FL 33458, USA
| | - Robert Huber
- JP Scott Center for Neuroscience, Mind & Behavior, Biological Sciences, Bowling Green State University, Bowling Green, OH 43614, USA; Radcliffe Institute for Advanced Study, Harvard University, 10 Garden Street, Cambridge, MA 02138, USA
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada; Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St. West, Suite 1400, Toronto, Ontario M5G 1Z8, Canada.
| |
Collapse
|
6
|
Teague C, Youngblood JP, Ragan K, Angilletta MJ, VandenBrooks JM. A positive genetic correlation between hypoxia tolerance and heat tolerance supports a controversial theory of heat stress. Biol Lett 2017; 13:rsbl.2017.0309. [PMID: 29118239 DOI: 10.1098/rsbl.2017.0309] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/18/2017] [Indexed: 11/12/2022] Open
Abstract
We used quantitative genetics to test a controversial theory of heat stress, in which animals overheat when the demand for oxygen exceeds the supply. This theory, referred to as oxygen- and capacity-limited thermal tolerance, predicts a positive genetic correlation between hypoxia tolerance and heat tolerance. We demonstrate the first genetic correlation of this kind in a model organism, Drosophila melanogaster Genotypes more likely to fly under hypoxic stress (12% O2) were also more likely to fly under heat stress (39°C). This finding prompts new questions about mechanisms and limits of adaptation to heat stress.
Collapse
Affiliation(s)
- Collin Teague
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | | | - Kinley Ragan
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | | | | |
Collapse
|
7
|
Kudow N, Miura D, Schleyer M, Toshima N, Gerber B, Tanimura T. Preference for and learning of amino acids in larval Drosophila. Biol Open 2017; 6:365-369. [PMID: 28193602 PMCID: PMC5374393 DOI: 10.1242/bio.020412] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis - and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.
Collapse
Affiliation(s)
- Nana Kudow
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Daisuke Miura
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Michael Schleyer
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Naoko Toshima
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan.,Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Bertram Gerber
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany.,Center for Behavioral Brain Sciences (CBBS), Universitätsplatz 2, 39106 Magdeburg, Germany.,Otto von Guericke University Magdeburg, Institute for Biology, Universitätsplatz 2, Magdeburg 39106, Germany
| | - Teiichi Tanimura
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan .,Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| |
Collapse
|
8
|
Mated Drosophila melanogaster females consume more amino acids during the dark phase. PLoS One 2017; 12:e0172886. [PMID: 28241073 PMCID: PMC5328406 DOI: 10.1371/journal.pone.0172886] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/10/2017] [Indexed: 11/19/2022] Open
Abstract
To maintain homeostasis, animals must ingest appropriate quantities, determined by their internal nutritional state, of suitable nutrients. In the fruit fly Drosophila melanogaster, an amino acid deficit induces a specific appetite for amino acids and thus results in their increased consumption. Although multiple processes of physiology, metabolism, and behavior are under circadian control in many organisms, it is unclear whether the circadian clock also modulates such motivated behavior driven by an internal need. Differences in levels of amino acid consumption by flies between the light and dark phases of the day:night cycle were examined using a capillary feeder assay following amino acid deprivation. Female flies exhibited increased consumption of amino acids during the dark phase compared with the light phase. Investigation of mutants lacking a functional period gene (per0), a well-characterized clock gene in Drosophila, found no difference between the light and dark phases in amino acid consumption by per0 flies. Furthermore, increased consumption of amino acids during the dark phase was observed in mated but not in virgin females, which strongly suggested that mating is involved in the rhythmic modulation of amino acid intake. Egg production, which is induced by mating, did not affect the rhythmic change in amino acid consumption, although egg-laying behavior showed a per0-dependent change in rhythm. Elevated consumption of amino acids during the dark phase was partly induced by the action of a seminal protein, sex peptide (SP), on the sex peptide receptor (SPR) in females. Moreover, we showed that the increased consumption of amino acids during the dark phase is induced in mated females independently of their internal level of amino acids. These results suggest that a post-mating SP/SPR signal elevates amino acid consumption during the dark phase via the circadian clock.
Collapse
|
9
|
Vertacnik KL, Linnen CR. Evolutionary genetics of host shifts in herbivorous insects: insights from the age of genomics. Ann N Y Acad Sci 2017; 1389:186-212. [DOI: 10.1111/nyas.13311] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/16/2016] [Accepted: 12/22/2016] [Indexed: 12/25/2022]
|
10
|
A molecular and neuronal basis for amino acid sensing in the Drosophila larva. Sci Rep 2016; 6:34871. [PMID: 27982028 PMCID: PMC5159833 DOI: 10.1038/srep34871] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/20/2016] [Indexed: 01/06/2023] Open
Abstract
Amino acids are important nutrients for animals, reflected in conserved internal pathways in vertebrates and invertebrates for monitoring cellular levels of these compounds. In mammals, sensory cells and metabotropic glutamate receptor-related taste receptors that detect environmental sources of amino acids in food are also well-characterised. By contrast, it is unclear how insects perceive this class of molecules through peripheral chemosensory mechanisms. Here we investigate amino acid sensing in Drosophila melanogaster larvae, which feed ravenously to support their rapid growth. We show that larvae display diverse behaviours (attraction, aversion, neutral) towards different amino acids, which depend upon stimulus concentration. Some of these behaviours require IR76b, a member of the variant ionotropic glutamate receptor repertoire of invertebrate chemoreceptors. IR76b is broadly expressed in larval taste neurons, suggesting a role as a co-receptor. We identify a subpopulation of these neurons that displays physiological activation by some, but not all, amino acids, and which mediate suppression of feeding by high concentrations of at least a subset of these compounds. Our data reveal the first elements of a sophisticated neuronal and molecular substrate by which these animals detect and behave towards external sources of amino acids.
Collapse
|
11
|
Recurrent specialization on a toxic fruit in an island Drosophila population. Proc Natl Acad Sci U S A 2016; 113:4771-6. [PMID: 27044093 DOI: 10.1073/pnas.1522559113] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recurrent specialization on similar host plants offers a unique opportunity to unravel the evolutionary and genetic mechanisms underlying dietary shifts. Recent studies have focused on ecological races belonging to the same species, but it is hard in many cases to untangle the role of adaptive introgression versus distinct mutations in facilitating recurrent evolution. We discovered on the island of Mayotte a population of the generalist fly Drosophila yakuba that is strictly associated with noni (Morinda citrifolia). This case strongly resembles Drosophila sechellia, a genetically isolated insular relative of D. yakuba whose intensely studied specialization on toxic noni fruits has always been considered a unique event in insect evolution. Experiments revealed that unlike mainland D. yakuba strains, Mayotte flies showed strong olfactory attraction and significant toxin tolerance to noni. Island females strongly discriminated against mainland males, suggesting that dietary adaptation has been accompanied by partial reproductive isolation. Population genomic analysis indicated a recent colonization (∼29 kya), at a time when year-round noni fruits may have presented a predictable resource on the small island, with ongoing migration after colonization. This relatively recent time scale allowed us to search for putatively adaptive loci based on genetic variation. Strong signals of genetic differentiation were found for several detoxification genes, including a major toxin tolerance locus in D. sechellia Our results suggest that recurrent evolution on a toxic resource can involve similar historical events and common genetic bases, and they establish an important genetic system for the study of early stages of ecological specialization and speciation.
Collapse
|
12
|
Yavuz A, Jagge C, Slone J, Amrein H. A genetic tool kit for cellular and behavioral analyses of insect sugar receptors. Fly (Austin) 2016; 8:189-96. [PMID: 25984594 DOI: 10.1080/19336934.2015.1050569] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Arthropods employ a large family of up to 100 putative taste or gustatory receptors (Grs) for the recognition of a wide range of non-volatile chemicals. In Drosophila melanogaster, a small subfamily of 8 Gr genes is thought to mediate the detection of sugars, the fly's major nutritional source. However, the specific roles for most sugar Gr genes are not known. Here, we report the generation of a series of mutant sugar Gr knock-in alleles and several composite sugar Gr mutant strains, including a sugar blind strain, which will facilitate the characterization of this gene family. Using Ca(2+) imaging experiments, we show that most gustatory receptor neurons (GRNs) of sugar blind flies (lacking all 8 sugar Gr genes) fail to respond to any sugar tested. Moreover, expression of single sugar Gr genes in most sweet GRNs of sugar-blind flies does not restore sugar responses. However, when pair-wise combinations of sugar Gr genes are introduced to sweet GRNs, responses to select sugars are restored. We also examined the cellular phenotype of flies homozygous mutant for Gr64a, a Gr gene previously reported to be a major contributor for the detection of many sugars. In contrast to these claims, we find that sweet GRNs of Gr64a homozygous mutant flies show normal responses to most sugars, and only modestly reduced responses to maltose and maltotriose. Thus, the precisely engineered genetic mutations of single Gr genes and construction of a sugar-blind strain provide powerful analytical tools for examining the roles of Drosophila and other insect sugar Gr genes in sweet taste.
Collapse
Affiliation(s)
- Ahmet Yavuz
- a Department of Cellular and Molecular Medicine ; Texas A&M Health Science Center ; College Station , TX USA
| | | | | | | |
Collapse
|
13
|
Garlapow ME, Huang W, Yarboro MT, Peterson KR, Mackay TFC. Quantitative Genetics of Food Intake in Drosophila melanogaster. PLoS One 2015; 10:e0138129. [PMID: 26375667 PMCID: PMC4574202 DOI: 10.1371/journal.pone.0138129] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 08/25/2015] [Indexed: 12/16/2022] Open
Abstract
Food intake is an essential animal activity, regulated by neural circuits that motivate food localization, evaluate nutritional content and acceptance or rejection responses through the gustatory system, and regulate neuroendocrine feedback loops that maintain energy homeostasis. Excess food consumption in people is associated with obesity and metabolic and cardiovascular disorders. However, little is known about the genetic basis of natural variation in food consumption. To gain insights in evolutionarily conserved genetic principles that regulate food intake, we took advantage of a model system, Drosophila melanogaster, in which food intake, environmental conditions and genetic background can be controlled precisely. We quantified variation in food intake among 182 inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP). We found significant genetic variation in the mean and within-line environmental variance of food consumption and observed sexual dimorphism and genetic variation in sexual dimorphism for both food intake traits (mean and variance). We performed genome wide association (GWA) analyses for mean food intake and environmental variance of food intake (using the coefficient of environmental variation, CVE, as the metric for environmental variance) and identified molecular polymorphisms associated with both traits. Validation experiments using RNAi-knockdown confirmed 24 of 31 (77%) candidate genes affecting food intake and/or variance of food intake, and a test cross between selected DGRP lines confirmed a SNP affecting mean food intake identified in the GWA analysis. The majority of the validated candidate genes were novel with respect to feeding behavior, and many had mammalian orthologs implicated in metabolic diseases.
Collapse
Affiliation(s)
- Megan E. Garlapow
- Program in Genetics, North Carolina State University, Raleigh, NC, 27695–7614, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, United States of America
- W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, 27695, United States of America
| | - Wen Huang
- Program in Genetics, North Carolina State University, Raleigh, NC, 27695–7614, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, United States of America
- W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, 27695, United States of America
| | - Michael T. Yarboro
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, United States of America
| | - Kara R. Peterson
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, United States of America
| | - Trudy F. C. Mackay
- Program in Genetics, North Carolina State University, Raleigh, NC, 27695–7614, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, United States of America
- W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, 27695, United States of America
- * E-mail:
| |
Collapse
|