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Bertinetti C, Härer A, Karagic N, Meyer A, Torres-Dowdall J. Repeated Divergence in Opsin Gene Expression Mirrors Photic Habitat Changes in Rapidly Evolving Crater Lake Cichlid Fishes. Am Nat 2024; 203:604-617. [PMID: 38635367 DOI: 10.1086/729420] [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] [Indexed: 04/20/2024]
Abstract
AbstractSelection pressures differ along environmental gradients, and traits tightly linked to fitness (e.g., the visual system) are expected to track such variation. Along gradients, adaptation to local conditions might be due to heritable and nonheritable environmentally induced variation. Disentangling these sources of phenotypic variation requires studying closely related populations in nature and in the laboratory. The Nicaraguan lakes represent an environmental gradient in photic conditions from clear crater lakes to very turbid great lakes. From two old, turbid great lakes, Midas cichlid fish (Amphilophus cf. citrinellus) independently colonized seven isolated crater lakes of varying light conditions, resulting in a small adaptive radiation. We estimated variation in visual sensitivities along this photic gradient by measuring cone opsin gene expression among lake populations. Visual sensitivities observed in all seven derived crater lake populations shifted predictably in direction and magnitude, repeatedly mirroring changes in photic conditions. Comparing wild-caught and laboratory-reared fish revealed that 48% of this phenotypic variation is genetically determined and evolved rapidly. Decreasing intrapopulation variation as environments become spectrally narrower suggests that different selective landscapes operate along the gradient. We conclude that the power to predict phenotypic evolution along gradients depends on both the magnitude of environmental change and the selective landscape shape.
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Schott RK, Fujita MK, Streicher JW, Gower DJ, Thomas KN, Loew ER, Bamba Kaya AG, Bittencourt-Silva GB, Guillherme Becker C, Cisneros-Heredia D, Clulow S, Davila M, Firneno TJ, Haddad CFB, Janssenswillen S, Labisko J, Maddock ST, Mahony M, Martins RA, Michaels CJ, Mitchell NJ, Portik DM, Prates I, Roelants K, Roelke C, Tobi E, Woolfolk M, Bell RC. Diversity and Evolution of Frog Visual Opsins: Spectral Tuning and Adaptation to Distinct Light Environments. Mol Biol Evol 2024; 41:msae049. [PMID: 38573520 PMCID: PMC10994157 DOI: 10.1093/molbev/msae049] [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: 09/12/2023] [Revised: 02/07/2024] [Accepted: 02/26/2024] [Indexed: 04/05/2024] Open
Abstract
Visual systems adapt to different light environments through several avenues including optical changes to the eye and neurological changes in how light signals are processed and interpreted. Spectral sensitivity can evolve via changes to visual pigments housed in the retinal photoreceptors through gene duplication and loss, differential and coexpression, and sequence evolution. Frogs provide an excellent, yet understudied, system for visual evolution research due to their diversity of ecologies (including biphasic aquatic-terrestrial life cycles) that we hypothesize imposed different selective pressures leading to adaptive evolution of the visual system, notably the opsins that encode the protein component of the visual pigments responsible for the first step in visual perception. Here, we analyze the diversity and evolution of visual opsin genes from 93 new eye transcriptomes plus published data for a combined dataset spanning 122 frog species and 34 families. We find that most species express the four visual opsins previously identified in frogs but show evidence for gene loss in two lineages. Further, we present evidence of positive selection in three opsins and shifts in selective pressures associated with differences in habitat and life history, but not activity pattern. We identify substantial novel variation in the visual opsins and, using microspectrophotometry, find highly variable spectral sensitivities, expanding known ranges for all frog visual pigments. Mutations at spectral-tuning sites only partially account for this variation, suggesting that frogs have used tuning pathways that are unique among vertebrates. These results support the hypothesis of adaptive evolution in photoreceptor physiology across the frog tree of life in response to varying environmental and ecological factors and further our growing understanding of vertebrate visual evolution.
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Affiliation(s)
- Ryan K Schott
- Department of Biology and Centre for Vision Research, York University, Toronto, Ontario, Canada
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Matthew K Fujita
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, USA
| | | | | | - Kate N Thomas
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, USA
- Natural History Museum, London, UK
| | - Ellis R Loew
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, USA
| | | | | | - C Guillherme Becker
- Department of Biology and One Health Microbiome Center, Center for Infectious Disease Dynamics, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Diego Cisneros-Heredia
- Laboratorio de Zoología Terrestre, Instituto de Biodiversidad Tropical IBIOTROP, Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito USFQ, Quito, Ecuador
| | - Simon Clulow
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Bruce, ACT, Australia
| | - Mateo Davila
- Laboratorio de Zoología Terrestre, Instituto de Biodiversidad Tropical IBIOTROP, Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito USFQ, Quito, Ecuador
| | - Thomas J Firneno
- Department of Biological Sciences, University of Denver, Denver, USA
| | - Célio F B Haddad
- Department of Biodiversity and Center of Aquaculture—CAUNESP, I.B., São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Sunita Janssenswillen
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jim Labisko
- Natural History Museum, London, UK
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
- Island Biodiversity and Conservation Centre, University of Seychelles, Mahé, Seychelles
| | - Simon T Maddock
- Natural History Museum, London, UK
- Island Biodiversity and Conservation Centre, University of Seychelles, Mahé, Seychelles
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Michael Mahony
- Department of Biological Sciences, The University of Newcastle, Newcastle 2308, Australia
| | - Renato A Martins
- Programa de Pós-graduação em Conservação da Fauna, Universidade Federal de São Carlos, São Carlos, Brazil
| | | | - Nicola J Mitchell
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Daniel M Portik
- Department of Herpetology, California Academy of Sciences, San Francisco, CA, USA
| | - Ivan Prates
- Department of Biology, Lund University, Lund, Sweden
| | - Kim Roelants
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Corey Roelke
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, USA
| | - Elie Tobi
- Gabon Biodiversity Program, Center for Conservation and Sustainability, Smithsonian National Zoo and Conservation Biology Institute, Gamba, Gabon
| | - Maya Woolfolk
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Rayna C Bell
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Department of Herpetology, California Academy of Sciences, San Francisco, CA, USA
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3
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Ricci V, Ronco F, Boileau N, Salzburger W. Visual opsin gene expression evolution in the adaptive radiation of cichlid fishes of Lake Tanganyika. SCIENCE ADVANCES 2023; 9:eadg6568. [PMID: 37672578 PMCID: PMC10482347 DOI: 10.1126/sciadv.adg6568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 08/07/2023] [Indexed: 09/08/2023]
Abstract
Tuning the visual sensory system to the ambient light is essential for survival in many animal species. This is often achieved through duplication, functional diversification, and/or differential expression of visual opsin genes. Here, we examined 753 new retinal transcriptomes from 112 species of cichlid fishes from Lake Tanganyika to unravel adaptive changes in gene expression at the macro-evolutionary and ecosystem level of one of the largest vertebrate adaptive radiations. We found that, across the radiation, all seven cone opsins-but not the rhodopsin-rank among the most differentially expressed genes in the retina, together with other vision-, circadian rhythm-, and hemoglobin-related genes. We propose two visual palettes characteristic of very shallow- and deep-water living species, respectively, and show that visual system adaptations along two major ecological axes, macro-habitat and diet, occur primarily via gene expression variation in a subset of cone opsin genes.
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Affiliation(s)
- Virginie Ricci
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Fabrizia Ronco
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Nicolas Boileau
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Walter Salzburger
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
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4
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Ricci V, Ronco F, Musilova Z, Salzburger W. Molecular evolution and depth-related adaptations of rhodopsin in the adaptive radiation of cichlid fishes in Lake Tanganyika. Mol Ecol 2022; 31:2882-2897. [PMID: 35302684 PMCID: PMC9314932 DOI: 10.1111/mec.16429] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/11/2022] [Accepted: 03/04/2022] [Indexed: 11/29/2022]
Abstract
The visual sensory system is essential for animals to perceive their environment and is thus under strong selection. In aquatic environments, light intensity and spectrum differ primarily along a depth gradient. Rhodopsin (RH1) is the only opsin responsible for dim‐light vision in vertebrates and has been shown to evolve in response to the respective light conditions, including along a water depth gradient in fishes. In this study, we examined the diversity and sequence evolution of RH1 in virtually the entire adaptive radiation of cichlid fishes in Lake Tanganyika, focusing on adaptations to the environmental light with respect to depth. We show that Tanganyikan cichlid genomes contain a single copy of RH1. The 76 variable amino acid sites detected in RH1 across the radiation were not uniformly distributed along the protein sequence, and 31 of these variable sites show signals of positive selection. Moreover, the amino acid substitutions at 15 positively selected sites appeared to be depth‐related, including three key tuning sites that directly mediate shifts in the peak spectral sensitivity, one site involved in protein stability and 11 sites that may be functionally important on the basis of their physicochemical properties. Among the strongest candidate sites for deep‐water adaptations are two known key tuning sites (positions 292 and 299) and three newly identified variable sites (37, 104 and 290). Our study, which is the first comprehensive analysis of RH1 evolution in a massive adaptive radiation of cichlid fishes, provides novel insights into the evolution of RH1 in a freshwater environment.
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Affiliation(s)
- Virginie Ricci
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Fabrizia Ronco
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Zuzana Musilova
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Walter Salzburger
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland
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5
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Schott RK, Perez L, Kwiatkowski MA, Imhoff V, Gumm JM. Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection. Ecol Evol 2022; 12:e8595. [PMID: 35154658 PMCID: PMC8820127 DOI: 10.1002/ece3.8595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 01/12/2023] Open
Abstract
Among major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, visual opsin genes, which encode the protein component of visual pigments, were obtained from anuran retinas. Additionally, we extracted the visual opsins from publicly available genome and transcriptome assemblies, further increasing the phylogenetic and ecological diversity of our dataset to 33 species in total. We found that anurans consistently express four visual opsin genes (RH1, LWS, SWS1, and SWS2, but not RH2) even though reported photoreceptor complements vary widely among species. The proteins encoded by these genes showed considerable sequence variation among species, including at sites known to shift the spectral sensitivity of visual pigments in other vertebrates and had conserved substitutions that may be related to dim-light adaptation. Using molecular evolutionary analyses of selection (dN/dS) we found significant evidence for positive selection at a subset of sites in the dim-light rod opsin gene RH1 and the long wavelength sensitive cone opsin LWS. The function of sites inferred to be under positive selection are largely unknown, but a few are likely to affect spectral sensitivity and other visual pigment functions based on proximity to previously identified sites in other vertebrates. We also found the first evidence of visual opsin duplication in an amphibian with the duplication of the LWS gene in the African bullfrog, which had distinct LWS copies on the sex chromosomes suggesting the possibility of sex-specific visual adaptation. Taken together, our results indicate that ecological factors, such as habitat and life history, as well as behavior, may be driving changes to anuran visual systems.
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Affiliation(s)
- Ryan K. Schott
- Department of BiologyYork UniversityTorontoOntarioCanada
- Department of Vertebrate ZoologyNational Museum of Natural HistorySmithsonian InstitutionWashingtonDistrict of ColumbiaUSA
| | - Leah Perez
- Department of BiologyStephen F. Austin State UniversityNacogdochesTexasUSA
| | | | - Vance Imhoff
- Southern Nevada Fish and Wildlife OfficeUS Fish and Wildlife ServiceLas VegasNevadaUSA
| | - Jennifer M. Gumm
- Department of BiologyStephen F. Austin State UniversityNacogdochesTexasUSA
- Ash Meadows Fish Conservation FacilityUS Fish and Wildlife ServiceAmargosa ValleyNevadaUSA
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6
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Schneider K, White TJ, Mitchell S, Adams CE, Reeve R, Elmer KR. The pitfalls and virtues of population genetic summary statistics: Detecting selective sweeps in recent divergences. J Evol Biol 2020; 34:893-909. [DOI: 10.1111/jeb.13738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 10/22/2020] [Accepted: 10/24/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Kevin Schneider
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
| | - Tom J. White
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
| | - Sonia Mitchell
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
| | - Colin E. Adams
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
- Scottish Centre for Ecology and the Natural Environment Institute of Biodiversity, Animal Health and Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
| | - Richard Reeve
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
| | - Kathryn R. Elmer
- Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK
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Carleton KL, Yourick MR. Axes of visual adaptation in the ecologically diverse family Cichlidae. Semin Cell Dev Biol 2020; 106:43-52. [PMID: 32439270 PMCID: PMC7486233 DOI: 10.1016/j.semcdb.2020.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 02/07/2023]
Abstract
The family Cichlidae contains approximately 2000 species that live in diverse freshwater habitats including murky lakes, turbid rivers, and clear lakes from both the Old and New Worlds. Their visual systems are similarly diverse and have evolved specific sensitivities that differ along several axes of variation. Variation in cornea and lens transmission affect which wavelengths reach the retina. Variation in photoreceptor number and distribution affect brightness sensitivity, spectral sensitivity and resolution. Probably their most dynamic characteristic is the variation in visual pigment peak sensitivities. Visual pigments can be altered through changes in chromophore, opsin sequence and opsin expression. Opsin expression varies by altering which of the seven available cone opsins in their genomes are turned on. These opsins can even be coexpressed to produce seemingly infinitely tunable cone sensitivities. Both chromophore and opsin expression can vary on either rapid (hours or days), slower (seasonal or ontogenetic) or evolutionary timescales. Such visual system shifts have enabled cichlids to adapt to different habitats and foraging styles. Through both short term plasticity and longer evolutionary adaptations, cichlids have proven to be ecologically successful and an excellent model for studying organismal adaptation.
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Affiliation(s)
- Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD, 20742, USA.
| | - Miranda R Yourick
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
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Carleton KL, Escobar-Camacho D, Stieb SM, Cortesi F, Marshall NJ. Seeing the rainbow: mechanisms underlying spectral sensitivity in teleost fishes. J Exp Biol 2020; 223:jeb193334. [PMID: 32327561 PMCID: PMC7188444 DOI: 10.1242/jeb.193334] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Among vertebrates, teleost eye diversity exceeds that found in all other groups. Their spectral sensitivities range from ultraviolet to red, and the number of visual pigments varies from 1 to over 40. This variation is correlated with the different ecologies and life histories of fish species, including their variable aquatic habitats: murky lakes, clear oceans, deep seas and turbulent rivers. These ecotopes often change with the season, but fish may also migrate between ecotopes diurnally, seasonally or ontogenetically. To survive in these variable light habitats, fish visual systems have evolved a suite of mechanisms that modulate spectral sensitivities on a range of timescales. These mechanisms include: (1) optical media that filter light, (2) variations in photoreceptor type and size to vary absorbance and sensitivity, and (3) changes in photoreceptor visual pigments to optimize peak sensitivity. The visual pigment changes can result from changes in chromophore or changes to the opsin. Opsin variation results from changes in opsin sequence, opsin expression or co-expression, and opsin gene duplications and losses. Here, we review visual diversity in a number of teleost groups where the structural and molecular mechanisms underlying their spectral sensitivities have been relatively well determined. Although we document considerable variability, this alone does not imply functional difference per se. We therefore highlight the need for more studies that examine species with known sensitivity differences, emphasizing behavioral experiments to test whether such differences actually matter in the execution of visual tasks that are relevant to the fish.
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Affiliation(s)
- Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Sara M Stieb
- Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
| | - Fabio Cortesi
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
| | - N Justin Marshall
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
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9
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Schneider RF, Rometsch SJ, Torres-Dowdall J, Meyer A. Habitat light sets the boundaries for the rapid evolution of cichlid fish vision, while sexual selection can tune it within those limits. Mol Ecol 2020; 29:1476-1493. [PMID: 32215986 DOI: 10.1111/mec.15416] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/07/2020] [Accepted: 03/16/2020] [Indexed: 12/30/2022]
Abstract
Cichlid fishes' famous diversity in body coloration is accompanied by a highly diverse and complex visual system. Although cichlids possess an unusually high number of seven cone opsin genes, they express only a subset of these during their ontogeny, accounting for their astonishing interspecific variation in visual sensitivities. Much of this diversity is thought to have been shaped by natural selection as cichlids inhabit a variety of habitats with distinct light environments. Also, sexual selection might have contributed to the observed visual diversity, and sexual dimorphism in coloration potentially co-evolved with sexual dimorphism in opsin expression. We investigated sex-specific opsin expression of several cichlids from Africa and the Neotropics and collected and integrated data sets on sex-specific body coloration, species-specific visual sensitivities, lens transmission and habitat light properties for some of them. We comparatively analysed this wide range of molecular and ecological data, illustrating how integrative approaches can address specific questions on the factors and mechanisms driving diversification, and the evolution of cichlid vision in particular. We found that both sexes expressed opsins at the same levels-even in sexually dimorphic cichlid species-which argues against coevolution of sexual dichromatism and differences in sex-specific visual sensitivity. Rather, a combination of environmental light properties and body coloration shaped the diversity in spectral sensitivities among cichlids. We conclude that although cichlids are particularly colourful and diverse and often sexually dimorphic, it would appear that natural rather than sexual selection is a more powerful force driving visual diversity in this hyperdiverse lineage.
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Affiliation(s)
- Ralph F Schneider
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany.,Department of Marine Ecology, GEOMAR, Kiel, Germany
| | - Sina J Rometsch
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Julián Torres-Dowdall
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany
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10
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Elbassiouny AA, Lovejoy NR, Chang BSW. Convergent patterns of evolution of mitochondrial oxidative phosphorylation (OXPHOS) genes in electric fishes. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190179. [PMID: 31787042 PMCID: PMC6939368 DOI: 10.1098/rstb.2019.0179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2019] [Indexed: 12/26/2022] Open
Abstract
The ability to generate and detect electric fields has evolved in several groups of fishes as a means of communication, navigation and, occasionally, predation. The energetic burden required can account for up to 20% of electric fishes' daily energy expenditure. Despite this, molecular adaptations that enable electric fishes to meet the metabolic demands of bioelectrogenesis remain unknown. Here, we investigate the molecular evolution of the mitochondrial oxidative phosphorylation (OXPHOS) complexes in the two most diverse clades of weakly electric fishes-South American Gymnotiformes and African Mormyroidea, using codon-based likelihood approaches. Our analyses reveal that although mitochondrial OXPHOS genes are generally subject to strong purifying selection, this constraint is significantly reduced in electric compared to non-electric fishes, particularly for complexes IV and V. Moreover, analyses of concatenated mitochondrial genes show strong evidence for positive selection in complex I genes on the two branches associated with the independent evolutionary origins of electrogenesis. These results suggest that adaptive evolution of proton translocation in the OXPHOS cellular machinery may be associated with the evolution of bioelectrogenesis. Overall, we find striking evidence for remarkably similar effects of electrogenesis on the molecular evolution of mitochondrial OXPHOS genes in two independently derived clades of electrogenic fishes. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Ahmed A. Elbassiouny
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
| | - Nathan R. Lovejoy
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
| | - Belinda S. W. Chang
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Centre for Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada
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11
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Schneider K, Adams CE, Elmer KR. Parallel selection on ecologically relevant gene functions in the transcriptomes of highly diversifying salmonids. BMC Genomics 2019; 20:1010. [PMID: 31870285 PMCID: PMC6929470 DOI: 10.1186/s12864-019-6361-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/01/2019] [Indexed: 12/11/2022] Open
Abstract
Background Salmonid fishes are characterised by a very high level of variation in trophic, ecological, physiological, and life history adaptations. Some salmonid taxa show exceptional potential for fast, within-lake diversification into morphologically and ecologically distinct variants, often in parallel; these are the lake-resident charr and whitefish (several species in the genera Salvelinus and Coregonus). To identify selection on genes and gene categories associated with such predictable diversifications, we analysed 2702 orthogroups (4.82 Mbp total; average 4.77 genes/orthogroup; average 1783 bp/orthogroup). We did so in two charr and two whitefish species and compared to five other salmonid lineages, which do not evolve in such ecologically predictable ways, and one non-salmonid outgroup. Results All selection analyses are based on Coregonus and Salvelinus compared to non-diversifying taxa. We found more orthogroups were affected by relaxed selection than intensified selection. Of those, 122 were under significant relaxed selection, with trends of an overrepresentation of serine family amino acid metabolism and transcriptional regulation, and significant enrichment of behaviour-associated gene functions. Seventy-eight orthogroups were under significant intensified selection and were enriched for signalling process and transcriptional regulation gene ontology terms and actin filament and lipid metabolism gene sets. Ninety-two orthogroups were under diversifying/positive selection. These were enriched for signal transduction, transmembrane transport, and pyruvate metabolism gene ontology terms and often contained genes involved in transcriptional regulation and development. Several orthogroups showed signs of multiple types of selection. For example, orthogroups under relaxed and diversifying selection contained genes such as ap1m2, involved in immunity and development, and slc6a8, playing an important role in muscle and brain creatine uptake. Orthogroups under intensified and diversifying selection were also found, such as genes syn3, with a role in neural processes, and ctsk, involved in bone remodelling. Conclusions Our approach pinpointed relevant genomic targets by distinguishing among different kinds of selection. We found that relaxed, intensified, and diversifying selection affect orthogroups and gene functions of ecological relevance in salmonids. Because they were found consistently and robustly across charr and whitefish and not other salmonid lineages, we propose these genes have a potential role in the replicated ecological diversifications.
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Affiliation(s)
- Kevin Schneider
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Colin E Adams
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.,Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, G63 0AW, UK
| | - Kathryn R Elmer
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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12
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Schott RK, Bhattacharyya N, Chang BS. Evolutionary signatures of photoreceptor transmutation in geckos reveal potential adaptation and convergence with snakes. Evolution 2019; 73:1958-1971. [DOI: 10.1111/evo.13810] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Ryan K. Schott
- Department of Ecology and Evolutionary BiologyUniversity of Toronto Toronto Ontario M5S 3G5 Canada
- Current Address: Department of Vertebrate Zoology, National Museum of Natural HistorySmithsonian Institution 10th and Constitution Ave NW Washington DC 20560‐0162
| | - Nihar Bhattacharyya
- Department of Cell and Systems BiologyUniversity of Toronto Toronto Ontario M5S 3G5 Canada
- Current Address: UCL Institute of Ophthalmology 11–43 Bath Street London EC1V 9EL United Kingdom
| | - Belinda S.W. Chang
- Department of Ecology and Evolutionary BiologyUniversity of Toronto Toronto Ontario M5S 3G5 Canada
- Department of Cell and Systems BiologyUniversity of Toronto Toronto Ontario M5S 3G5 Canada
- Centre for the Analysis of Genome Evolution and FunctionUniversity of Toronto Toronto Ontario M5S 3B2 Canada
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13
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Gutierrez EDA, Castiglione GM, Morrow JM, Schott RK, Loureiro LO, Lim BK, Chang BSW. Functional Shifts in Bat Dim-Light Visual Pigment Are Associated with Differing Echolocation Abilities and Reveal Molecular Adaptation to Photic-Limited Environments. Mol Biol Evol 2019; 35:2422-2434. [PMID: 30010964 DOI: 10.1093/molbev/msy140] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Bats are excellent models for studying the molecular basis of sensory adaptation. In Chiroptera, a sensory trade-off has been proposed between the visual and auditory systems, though the extent of this association has yet to be fully examined. To investigate whether variation in visual performance is associated with echolocation, we experimentally assayed the dim-light visual pigment rhodopsin from bat species with differing echolocation abilities. While spectral tuning properties were similar among bats, we found that the rate of decay of their light-activated state was significantly slower in a nonecholocating bat relative to species that use distinct echolocation strategies, consistent with a sensory trade-off hypothesis. We also found that these rates of decay were remarkably slower compared with those of other mammals, likely indicating an adaptation to dim light. To examine whether functional changes in rhodopsin are associated with shifts in selection intensity upon bat Rh1 sequences, we implemented selection analyses using codon-based likelihood clade models. While no shifts in selection were identified in response to diverse echolocation abilities of bats, we detected a significant increase in the intensity of evolutionary constraint accompanying the diversification of Chiroptera. Taken together, this suggests that substitutions that modulate the stability of the light-activated rhodopsin state were likely maintained through intensified constraint after bats diversified, being finely tuned in response to novel sensory specializations. Our study demonstrates the power of combining experimental and computational approaches for investigating functional mechanisms underlying the evolution of complex sensory adaptations.
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Affiliation(s)
- Eduardo de A Gutierrez
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Gianni M Castiglione
- Department of Cell and Systems Biology, University of Toronto, ON, Canada.,Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James M Morrow
- Department of Cell and Systems Biology, University of Toronto, ON, Canada.,Centre of Forensic Sciences, Toronto, ON, Canada
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Livia O Loureiro
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Burton K Lim
- Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, ON, Canada.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, Canada
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14
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Gutierrez EDA, Schott RK, Preston MW, Loureiro LO, Lim BK, Chang BSW. The role of ecological factors in shaping bat cone opsin evolution. Proc Biol Sci 2019; 285:rspb.2017.2835. [PMID: 29618549 DOI: 10.1098/rspb.2017.2835] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/15/2018] [Indexed: 12/16/2022] Open
Abstract
Bats represent one of the largest and most striking nocturnal mammalian radiations, exhibiting many visual system specializations for performance in light-limited environments. Despite representing the greatest ecological diversity and species richness in Chiroptera, Neotropical lineages have been undersampled in molecular studies, limiting the potential for identifying signatures of selection on visual genes associated with differences in bat ecology. Here, we investigated how diverse ecological pressures mediate long-term shifts in selection upon long-wavelength (Lws) and short-wavelength (Sws1) opsins, photosensitive cone pigments that form the basis of colour vision in most mammals, including bats. We used codon-based likelihood clade models to test whether ecological variables associated with reliance on visual information (e.g. echolocation ability and diet) or exposure to varying light environments (e.g. roosting behaviour and foraging habitat) mediated shifts in evolutionary rates in bat cone opsin genes. Using additional cone opsin sequences from newly sequenced eye transcriptomes of six Neotropical bat species, we found significant evidence for different ecological pressures influencing the evolution of the cone opsins. While Lws is evolving under significantly lower constraint in highly specialized high-duty cycle echolocating lineages, which have enhanced sonar ability to detect and track targets, variation in Sws1 constraint was significantly associated with foraging habitat, exhibiting elevated rates of evolution in species that forage among vegetation. This suggests that increased reliance on echolocation as well as the spectral environment experienced by foraging bats may differentially influence the evolution of different cone opsins. Our study demonstrates that different ecological variables may underlie contrasting evolutionary patterns in bat visual opsins, and highlights the suitability of clade models for testing ecological hypotheses of visual evolution.
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Affiliation(s)
- Eduardo de A Gutierrez
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Matthew W Preston
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Lívia O Loureiro
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Burton K Lim
- Department of Natural History, Royal Ontario Museum, Toronto, Ontario, Canada M5S 2C6
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 .,Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2.,Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
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15
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Schott RK, Van Nynatten A, Card DC, Castoe TA, S W Chang B. Shifts in Selective Pressures on Snake Phototransduction Genes Associated with Photoreceptor Transmutation and Dim-Light Ancestry. Mol Biol Evol 2019; 35:1376-1389. [PMID: 29800394 DOI: 10.1093/molbev/msy025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The visual systems of snakes are heavily modified relative to other squamates, a condition often thought to reflect their fossorial origins. Further modifications are seen in caenophidian snakes, where evolutionary transitions between rod and cone photoreceptors, termed photoreceptor transmutations, have occurred in many lineages. Little previous work, however, has focused on the molecular evolutionary underpinnings of these morphological changes. To address this, we sequenced seven snake eye transcriptomes and utilized new whole-genome and targeted capture sequencing data. We used these data to analyze gene loss and shifts in selection pressures in phototransduction genes that may be associated with snake evolutionary origins and photoreceptor transmutation. We identified the surprising loss of rhodopsin kinase (GRK1), despite a low degree of gene loss overall and a lack of relaxed selection early during snake evolution. These results provide some of the first evolutionary genomic corroboration for a dim-light ancestor that lacks strong fossorial adaptations. Our results also indicate that snakes with photoreceptor transmutation experienced significantly different selection pressures from other reptiles. Significant positive selection was found primarily in cone-specific genes, but not rod-specific genes, contrary to our expectations. These results reveal potential molecular adaptations associated with photoreceptor transmutation and also highlight unappreciated functional differences between rod- and cone-specific phototransduction proteins. This intriguing example of snake visual system evolution illustrates how the underlying molecular components of a complex system can be reshaped in response to changing selection pressures.
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Affiliation(s)
- Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | | | - Daren C Card
- Department of Biology, University of Texas, Arlington, TX
| | - Todd A Castoe
- Department of Biology, University of Texas, Arlington, TX
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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16
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Escobar-Camacho D, Pierotti MER, Ferenc V, Sharpe DMT, Ramos E, Martins C, Carleton KL. Variable vision in variable environments: the visual system of an invasive cichlid ( Cichla monoculus) in Lake Gatun, Panama. ACTA ACUST UNITED AC 2019; 222:jeb.188300. [PMID: 30787138 DOI: 10.1242/jeb.188300] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 02/10/2019] [Indexed: 01/11/2023]
Abstract
An adaptive visual system is essential for organisms inhabiting new or changing light environments. The Panama Canal exhibits such variable environments owing to its anthropogenic origin and current human activities. Within the Panama Canal, Lake Gatun harbors several exotic fish species including the invasive peacock bass (Cichla monoculus), a predatory Amazonian cichlid. In this research, through spectral measurements and molecular and physiological experiments, we studied the visual system of C. monoculus and its adaptive capabilities. Our results suggest that (1) Lake Gatun is a highly variable environment, where light transmission changes throughout the canal waterway, and that (2) C. monoculus has several visual adaptations suited for this red-shifted light environment. Cichla monoculus filters short wavelengths (∼400 nm) from the environment through its ocular media and tunes its visual sensitivities to the available light through opsin gene expression. More importantly, based on shifts in spectral sensitivities of photoreceptors alone, and on transcriptome analysis, C. monoculus exhibits extreme intraspecific variation in the use of vitamin A1/A2 chromophore in their photoreceptors. Fish living in turbid water had higher proportions of vitamin A2, shifting sensitivities to longer wavelengths, than fish living in clear water. Furthermore, we also found variation in retinal transcriptomes, where fish from turbid and clear waters exhibited differentially expressed genes that vary greatly in their function. We suggest that this phenotypic plasticity has been key in the invasion success of C. monoculus.
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Affiliation(s)
| | - Michele E R Pierotti
- Naos Marine Laboratories, Smithsonian Tropical Research Institute, Calzada de Amador, Bld 356, 0843-03092 Panama, Republic of Panama
| | - Viktoria Ferenc
- Plant Ecology Group, Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 5, 72076 Tübingen, Germany
| | - Diana M T Sharpe
- Naos Marine Laboratories, Smithsonian Tropical Research Institute, Calzada de Amador, Bld 356, 0843-03092 Panama, Republic of Panama
| | - Erica Ramos
- Department of Morphology, Biosciences Institute, São Paulo State University, Botucatu 18618-689, Brazil
| | - Cesar Martins
- Department of Morphology, Biosciences Institute, São Paulo State University, Botucatu 18618-689, Brazil
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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17
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Irisarri I, Singh P, Koblmüller S, Torres-Dowdall J, Henning F, Franchini P, Fischer C, Lemmon AR, Lemmon EM, Thallinger GG, Sturmbauer C, Meyer A. Phylogenomics uncovers early hybridization and adaptive loci shaping the radiation of Lake Tanganyika cichlid fishes. Nat Commun 2018; 9:3159. [PMID: 30089797 PMCID: PMC6082878 DOI: 10.1038/s41467-018-05479-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 05/30/2018] [Indexed: 11/21/2022] Open
Abstract
Lake Tanganyika is the oldest and phenotypically most diverse of the three East African cichlid fish adaptive radiations. It is also the cradle for the younger parallel haplochromine cichlid radiations in Lakes Malawi and Victoria. Despite its evolutionary significance, the relationships among the main Lake Tanganyika lineages remained unresolved, as did the general timescale of cichlid evolution. Here, we disentangle the deep phylogenetic structure of the Lake Tanganyika radiation using anchored phylogenomics and uncover hybridization at its base, as well as early in the haplochromine radiation. This suggests that hybridization might have facilitated these speciation bursts. Time-calibrated trees support that the radiation of Tanganyika cichlids coincided with lake formation and that Gondwanan vicariance concurred with the earliest splits in the cichlid family tree. Genes linked to key innovations show signals of introgression or positive selection following colonization of lake habitats and species' dietary adaptations are revealed as major drivers of colour vision evolution. These findings shed light onto the processes shaping the evolution of adaptive radiations.
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Affiliation(s)
- Iker Irisarri
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal, 2, Madrid, 28006, Spain
| | - Pooja Singh
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Institute of Biology, University of Graz, Universitätsplatz 2, Graz, 8010, Austria
| | - Stephan Koblmüller
- Institute of Biology, University of Graz, Universitätsplatz 2, Graz, 8010, Austria
| | - Julián Torres-Dowdall
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
| | - Frederico Henning
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, 21944-970, Brazil
| | - Paolo Franchini
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany
| | - Christoph Fischer
- Institute of Computational Biotechnology, Graz University of Technology, Petersgasse 14, Graz, 8010, Austria
- OMICS Center Graz, BioTechMed Graz, Stiftingtalstraße 24, Graz, 8010, Austria
| | - Alan R Lemmon
- Department of Scientific Computing, Florida State University, Dirac Science Library, Tallahassee, FL, 32306, USA
| | - Emily Moriarty Lemmon
- Department of Biological Science, Florida State University, Biomedical Research Facility, Tallahassee, FL, 32306, USA
| | - Gerhard G Thallinger
- Institute of Computational Biotechnology, Graz University of Technology, Petersgasse 14, Graz, 8010, Austria
- OMICS Center Graz, BioTechMed Graz, Stiftingtalstraße 24, Graz, 8010, Austria
| | - Christian Sturmbauer
- Institute of Biology, University of Graz, Universitätsplatz 2, Graz, 8010, Austria.
| | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, 78457, Germany.
- Radcliffe Institute for Advanced Study, Harvard University, Cambridge, 02138, MA, USA.
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18
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Härer A, Meyer A, Torres‐Dowdall J. Convergent phenotypic evolution of the visual system via different molecular routes: How Neotropical cichlid fishes adapt to novel light environments. Evol Lett 2018; 2:341-354. [PMID: 30283686 PMCID: PMC6121847 DOI: 10.1002/evl3.71] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 12/17/2022] Open
Abstract
How predictable is evolution? This remains a fundamental but contested issue in evolutionary biology. When independent lineages colonize the same environment, we are presented with a natural experiment that allows us to ask if genetic and ecological differences promote species-specific evolutionary outcomes or whether species phenotypically evolve in a convergent manner in response to shared selection pressures. If so, are the molecular mechanisms underlying phenotypic convergence the same? In Nicaragua, seven species of cichlid fishes concurrently colonized two novel photic environments. Hence, their visual system represents a compelling model to address these questions, particularly since the adaptive value of phenotypic changes is well-understood. By analyzing retinal transcriptomes, we found that differential expression of genes responsible for color vision (cone opsins and cyp27c1) produced rapid and mostly convergent changes of predicted visual sensitivities. Notably, these changes occurred in the same direction in all species although there were differences in underlying gene expression patterns illustrating nonconvergence at the molecular level. Adaptive phenotypes evolved deterministically, even when species differ substantially in ecology and genetic variation. This provides strong evidence that phenotypic evolution of the visual system occurred in response to similar selective forces of the photic environment.
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Affiliation(s)
- Andreas Härer
- Zoology and Evolutionary Biology, Department of BiologyUniversity of KonstanzGermany
| | - Axel Meyer
- Zoology and Evolutionary Biology, Department of BiologyUniversity of KonstanzGermany
- Radcliffe Institute for Advanced StudyHarvard UniversityCambridgeMassachusetts02138
| | - Julián Torres‐Dowdall
- Zoology and Evolutionary Biology, Department of BiologyUniversity of KonstanzGermany
- Zukunftskolleg, University of KonstanzKonstanzGermany
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19
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Hauser FE, Ilves KL, Schott RK, Castiglione GM, López-Fernández H, Chang BSW. Accelerated Evolution and Functional Divergence of the Dim Light Visual Pigment Accompanies Cichlid Colonization of Central America. Mol Biol Evol 2017; 34:2650-2664. [PMID: 28957507 DOI: 10.1093/molbev/msx192] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cichlids encompass one of the most diverse groups of fishes in South and Central America, and show extensive variation in life history, morphology, and colouration. While studies of visual system evolution in cichlids have focussed largely on the African rift lake species flocks, Neotropical cichlids offer a unique opportunity to investigate visual system evolution at broader temporal and geographic scales. South American cichlid colonization of Central America has likely promoted accelerated rates of morphological evolution in Central American lineages as they encountered reduced competition, renewed ecological opportunity, and novel aquatic habitats. To investigate whether such transitions have influenced molecular evolution of vision in Central American cichlids, we sequenced the dim-light rhodopsin gene in 101 Neotropical cichlid species, spanning the diversity of the clade. We find strong evidence for increased rates of evolution in Central American cichlid rhodopsin relative to South American lineages, and identify several sites under positive selection in rhodopsin that likely contribute to adaptation to different photic environments. We expressed a Neotropical cichlid rhodopsin protein invitro for the first time, and found that while its spectral tuning properties were characteristic of typical vertebrate rhodopsin pigments, the rate of decay of its active signalling form was much slower, consistent with dim light adaptation in other vertebrate rhodopsins. Using site-directed mutagenesis combined with spectroscopic assays, we found that a key amino acid substitution present in some Central American cichlids accelerates the rate of decay of active rhodopsin, which may mediate adaptation to clear water habitats.
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Affiliation(s)
- Frances E Hauser
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Katriina L Ilves
- Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
- Department of Biology, Pace University, New York, NY
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Gianni M Castiglione
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, Canada
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20
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Insights into visual pigment adaptation and diversity from model ecological and evolutionary systems. Curr Opin Genet Dev 2017; 47:110-120. [PMID: 29102895 DOI: 10.1016/j.gde.2017.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/18/2017] [Accepted: 09/29/2017] [Indexed: 01/07/2023]
Abstract
Sensory systems provide valuable insight into the evolution of molecular mechanisms underlying organismal anatomy, physiology, and behaviour. Visual pigments, which mediate the first step in visual transduction, offer a unique window into the relationship between molecular variation and visual performance, and enhance our understanding of how ecology, life history, and physiology may shape genetic variation across a variety of organisms. Here we review recent work investigating vertebrate visual pigments from a number of perspectives. Opsin gene duplication, loss, differential expression, structural variation, and the physiological context in which they operate, have profoundly shaped the visual capabilities of vertebrates adapting to novel environments. We note the importance of conceptual frameworks in investigating visual pigment diversity in vertebrates, highlighting key examples including evolutionary transitions between different photic environments, major shifts in life history evolution and ecology, evolutionary innovations in visual system anatomy and physiology, as well as shifts in visually mediated behaviours and behavioural ecology. We emphasize the utility of studying visual pigment evolution in the context of these different perspectives, and demonstrate how the integrative approaches discussed in this review contribute to a better understanding of the underlying molecular processes mediating adaptation in sensory systems, and the contexts in which they occur.
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21
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Torres-Dowdall J, Pierotti ME, Härer A, Karagic N, Woltering JM, Henning F, Elmer KR, Meyer A. Rapid and Parallel Adaptive Evolution of the Visual System of Neotropical Midas Cichlid Fishes. Mol Biol Evol 2017; 34:2469-2485. [DOI: 10.1093/molbev/msx143] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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22
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Escobar-Camacho D, Ramos E, Martins C, Carleton KL. The opsin genes of amazonian cichlids. Mol Ecol 2017; 26:1343-1356. [PMID: 27997048 PMCID: PMC5342946 DOI: 10.1111/mec.13957] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/04/2016] [Accepted: 11/21/2016] [Indexed: 01/30/2023]
Abstract
Vision is a critical sense for organismal survival with visual sensitivities strongly shaped by the environment. Some freshwater fishes with a Gondwanan origin are distributed in both South American rivers including the Amazon and African rivers and lakes. These different habitats likely required adaptations to murky and clear environments. In this study, we compare the molecular basis of Amazonian and African cichlid fishes' visual systems. We used next-generation sequencing of genomes and retinal transcriptomes to examine three Amazonian cichlid species. Genome assemblies revealed six cone opsin classes (SWS1, SWS2B, SWS2A, RH2B, RH2A and LWS) and rod opsin (RH1). However, the functionality of these genes varies across species with different pseudogenes found in different species. Our results support evidence of an RH2A gene duplication event that is shared across both cichlid groups, but which was probably followed by gene conversion. Transcriptome analyses show that Amazonian species mainly express three opsin classes (SWS2A, RH2A and LWS), which likely are a good match to the long-wavelength-oriented light environment of the Amazon basin. Furthermore, analysis of amino acid sequences suggests that the short-wavelength-sensitive genes (SWS2B, SWS2A) may be under selective pressures to shift their spectral properties to a longer-wavelength visual palette. Our results agree with the 'sensitivity hypothesis' where the light environment causes visual adaptation. Amazonian cichlid visual systems are likely adapting through gene expression, gene loss and possibly spectral tuning of opsin sequences. Such mechanisms may be shared across the Amazonian fish fauna.
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Affiliation(s)
| | - Erica Ramos
- Department of Morphology, Biosciences Institute, São Paulo State University, 18618-689 Botucatu, Brazil
| | - Cesar Martins
- Department of Morphology, Biosciences Institute, São Paulo State University, 18618-689 Botucatu, Brazil
| | - Karen L. Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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23
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Maan ME, Seehausen O, Groothuis TGG. Differential Survival between Visual Environments Supports a Role of Divergent Sensory Drive in Cichlid Fish Speciation. Am Nat 2017; 189:78-85. [DOI: 10.1086/689605] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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24
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Carleton KL, Dalton BE, Escobar-Camacho D, Nandamuri SP. Proximate and ultimate causes of variable visual sensitivities: Insights from cichlid fish radiations. Genesis 2016; 54:299-325. [PMID: 27061347 DOI: 10.1002/dvg.22940] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 01/24/2023]
Abstract
Animals vary in their sensitivities to different wavelengths of light. Sensitivity differences can have fitness implications in terms of animals' ability to forage, find mates, and avoid predators. As a result, visual systems are likely selected to operate in particular lighting environments and for specific visual tasks. This review focuses on cichlid vision, as cichlids have diverse visual sensitivities, and considerable progress has been made in determining the genetic basis for this variation. We describe both the proximate and ultimate mechanisms shaping cichlid visual diversity using the structure of Tinbergen's four questions. We describe (1) the molecular mechanisms that tune visual sensitivities including changes in opsin sequence and expression; (2) the evolutionary history of visual sensitivity across the African cichlid flocks; (3) the ontological changes in visual sensitivity and how modifying this developmental program alters sensitivities among species; and (4) the fitness benefits of spectral tuning mechanisms with respect to survival and mating success. We further discuss progress to unravel the gene regulatory networks controlling opsin expression and suggest that a simple genetic architecture contributes to the lability of opsin gene expression. Finally, we identify unanswered questions including whether visual sensitivities are experiencing selection, and whether similar spectral tuning mechanisms shape visual sensitivities of other fishes. genesis 54:299-325, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Karen L Carleton
- Department of Biology, University of Maryland, College Park, Maryland
| | - Brian E Dalton
- Department of Biology, University of Maryland, College Park, Maryland
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