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Tetrault E, Aaronson B, Gilbert MC, Albertson RC. Foraging-induced craniofacial plasticity is associated with an early, robust and dynamic transcriptional response. Proc Biol Sci 2024; 291:20240215. [PMID: 38654651 PMCID: PMC11040245 DOI: 10.1098/rspb.2024.0215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 03/19/2024] [Indexed: 04/26/2024] Open
Abstract
Phenotypic plasticity is the ability of a single genotype to vary its phenotype in response to the environment. Plasticity of the skeletal system in response to mechanical input is widely studied, but the timing of its transcriptional regulation is not well understood. Here, we used the cichlid feeding apparatus to examine the transcriptional dynamics of skeletal plasticity over time. Using three closely related species that vary in their ability to remodel bone and a panel of 11 genes, including well-studied skeletal differentiation markers and newly characterized environmentally sensitive genes, we examined plasticity at one, two, four and eight weeks following the onset of alternate foraging challenges. We found that the plastic species exhibited environment-specific bursts in gene expression beginning at one week, followed by a sharp decline in levels, while the species with more limited plasticity exhibited consistently low levels of gene expression. This trend held across nearly all genes, suggesting that it is a hallmark of the larger plasticity regulatory network. We conclude that plasticity of the cichlid feeding apparatus is not the result of slowly accumulating gene expression difference over time, but rather is stimulated by early bursts of environment-specific gene expression followed by a return to homeostatic levels.
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Affiliation(s)
- Emily Tetrault
- Molecular and Cell Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Ben Aaronson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Michelle C. Gilbert
- Department of Biology, Pennsylvania State University, State College, PA 16802, USA
| | - R. Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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2
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DeLorenzo L, Powder KE. Epigenetics and the evolution of form: Experimental manipulation of a chromatin modification causes species-specific changes to the craniofacial skeleton. Evol Dev 2024; 26:e12461. [PMID: 37850843 PMCID: PMC10842503 DOI: 10.1111/ede.12461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 08/18/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023]
Abstract
A central question in biology is the molecular origins of phenotypic diversity. While genetic changes are key to the genotype-phenotype relationship, alterations to chromatin structure and the physical packaging of histone proteins may also be important drivers of vertebrate divergence. We investigate the impact of such an epigenetic mechanism, histone acetylation, within a textbook example of an adaptive radiation. Cichlids of Lake Malawi have adapted diverse craniofacial structures, and here we investigate how histone acetylation influences morphological variation in these fishes. Specifically, we assessed the effect of inhibiting histone deacetylation using the drug trichostatin A (TSA) on developing facial structures. We examined this during three critical developmental windows in two cichlid species with alternate adult morphologies. Exposure to TSA during neural crest cell (NCC) migration and as postmigratory NCCs proliferate in the pharyngeal arches resulted in significant changes in lateral and ventral shape in Maylandia, but not in Tropheops. This included an overall shortening of the head, widening of the lower jaw, and steeper craniofacial profile, all of which are paedomorphic morphologies. In contrast, treatment with TSA during early chondrogenesis did not result in significant morphological changes in either species. Together, these data suggest a sensitivity to epigenetic alterations that are both time- and species-dependent. We find that morphologies are due to nonautonomous or potentially indirect effects on NCC development, including in part a global developmental delay. Our research bolsters the understanding that proper histone acetylation is essential for early craniofacial development and identifies a species-specific robustness to developmental change. Overall, this study demonstrates how epigenetic regulation may play an important role in both generating and buffering morphological variation.
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Affiliation(s)
- Leah DeLorenzo
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Kara E Powder
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
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3
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McWhinnie K, Negi D, Tanner KE, Parsons KJ. Functional trait plasticity diverges between sexes in African cichlids: A contribution toward ecological sexual dimorphism? Ecol Evol 2023; 13:e10702. [PMID: 38034329 PMCID: PMC10682861 DOI: 10.1002/ece3.10702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 08/02/2023] [Accepted: 08/17/2023] [Indexed: 12/02/2023] Open
Abstract
Phenotypic plasticity enables development to produce multiple phenotypes in response to environmental conditions. Plasticity driven variation has been suggested to play a key role in adaptive divergence, and plasticity itself can evolve. However, the interaction of plasticity with the multiple levels involved with adaptive divergence is less understood. For example, sexual dimorphism can contribute adaptive variation through ecological sexual dimorphism (ESD), but the contribution of plasticity to this phenomenon is unknown. Therefore, to determine the potential contribution of plasticity to ESD, we used the adaptive radiation of Malawi cichlids. Two mouthbrooding species (Labeotropheus fuelleborni and Tropheops "Red Cheek") with differences in foraging tactics underwent foraging experiments using benthic and limnetic treatments while accounting for sex. Plasticity in craniofacial shape and three functionally important traits were measured. Plasticity was shown, but without any sex-based differences in shape. However, for mechanical advantage traits of the mandible sex by diet interactions were found. This suggests that ESD, may be influenced by phenotypic plasticity that diverges between sexes. Given the involvement of the mandible in parental care in cichlids this may indicate that sexual divergence in plasticity may trade-off against maternal care tactics.
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Affiliation(s)
- Kirsty McWhinnie
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Deepti Negi
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - K. Elizabeth Tanner
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
- School of Engineering and Materials ScienceQueen Mary University of LondonLondonUK
| | - Kevin J. Parsons
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
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4
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Tetrault E, Swenson J, Aaronson B, Marcho C, Albertson RC. The transcriptional state and chromatin landscape of cichlid jaw shape variation across species and environments. Mol Ecol 2023; 32:3922-3941. [PMID: 37160741 PMCID: PMC10524807 DOI: 10.1111/mec.16975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/11/2023]
Abstract
Adaptive phenotypes are shaped by a combination of genetic and environmental forces, but how they interact remains poorly understood. Here, we utilize the cichlid oral jaw apparatus to better understand these gene-by-environment effects. First, we employed RNA-seq in bony and ligamentous tissues important for jaw opening to identify differentially expressed genes between species and across foraging environments. We used two Lake Malawi species adapted to different foraging habitats along the pelagic-benthic ecomorphological axis. Our foraging treatments were designed to force animals to employ either suction or biting/scraping, which broadly mimic pelagic or benthic modes of feeding. We found a large number of differentially expressed genes between species, and while we identified relatively few differences between environments, species differences were far more pronounced when they were challenged with a pelagic versus benthic foraging mode. Expression data carried the signature of genetic assimilation, and implicated cell cycle regulation in shaping the jaw across species and environments. Next, we repeated the foraging experiment and performed ATAC-seq procedures on nuclei harvested from the same tissues. Cross-referencing results from both analyses revealed subsets of genes that were both differentially expressed and differentially accessible. This reduced dataset implicated notable candidate genes including the Hedgehog effector, KIAA0586 and the ETS transcription factor, etv4, which connects environmental stress and craniofacial morphogenesis. Taken together, these data provide novel insights into the epigenetic, genetic and cellular bases of species- and environment-specific bone shapes.
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Affiliation(s)
- Emily Tetrault
- Graduate Program in Molecular and Cell Biology, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - John Swenson
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - Ben Aaronson
- Biology Department, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - Chelsea Marcho
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst MA, 01003, U.S.A
| | - R. Craig Albertson
- Biology Department, University of Massachusetts, Amherst MA, 01003, U.S.A
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5
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Bose APH, Dabernig-Heinz J, Oberkofler J, Koch L, Grimm J, Sefc KM, Jordan A. Aggression and spatial positioning of kin and non-kin fish in social groups. Behav Ecol 2023; 34:673-681. [PMID: 37434638 PMCID: PMC10332448 DOI: 10.1093/beheco/arad036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 04/01/2023] [Accepted: 04/19/2023] [Indexed: 07/13/2023] Open
Abstract
Group-living animals are faced with the challenge of sharing space and local resources amongst group members who may be either relatives or non-relatives. Individuals may reduce the inclusive fitness costs they incur from competing with relatives by either reducing their levels of aggression toward kin, or by maintaining physical separation between kin. In this field study, we used the group-living cichlid Neolamprologus multifasciatus to examine whether within-group aggression is reduced among group members that are kin, and whether kin occupy different regions of their group's territory to reduce kin competition over space and local resources. We determined the kinship relationships among cohabiting adults via microsatellite genotyping and then combined these with spatial and behavioral analyses of groups in the wild. We found that aggressive contests between group members declined in frequency with spatial separation between their shelters. Female kin did not engage in aggressive contests with one another, whereas non-kin females did, despite the fact these females lived at similar distances from one another on their groups' territories. Contests within male-male and male-female dyads did not clearly correlate with kinship. Non-kin male-male and male-female dyads lived at more variable distances from one another on their territories than their corresponding kin dyads. Together, our study indicates that contests among group members can be mediated by relatedness in a sex-dependent manner. We also suggest that spatial relationships can play an important role in determining the extent to which group members compete with one another.
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Affiliation(s)
- Aneesh P H Bose
- Department of Wildlife, Fish & Environmental Studies, Swedish University of Agricultural Sciences (SLU), Skogsmarksgränd, 90183, Umeå, Sweden
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | | | - Jan Oberkofler
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Lukas Koch
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Jacqueline Grimm
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Kristina M Sefc
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Alex Jordan
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
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6
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Li CY, Lawrence K, Merlo-Coyne J, Juntti SA. Prostaglandin F(2α) drives female pheromone signaling in cichlids, revealing a basis for evolutionary divergence in olfactory signaling. Proc Natl Acad Sci U S A 2023; 120:e2214418120. [PMID: 36584295 DOI: 10.1073/pnas.2214418120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pheromones play essential roles in reproduction in many species. Prostaglandin F2α (PGF2α) acts as a female reproductive hormone and as a sex pheromone in some species. An olfactory receptor (OR) for PGF2α was recently discovered in zebrafish, but this signaling pathway is evolutionarily labile. To understand the evolution of signals that attract males to fertile females, we used the African cichlid Astatotilapia burtoni and found that adult males strongly prefer fertile female odors. Injection of a prostaglandin synthesis inhibitor abolishes this attractivity of fertile females, indicating these hormones are necessary for pheromonal signaling. Unlike zebrafish, A. burtoni males are insensitive to PGF2α, but they do exhibit strong preference for females injected with PGF2α. This attractiveness is independent of the PGF2α hormonal receptor Ptgfr, indicating that this pheromone signaling derives from PGF2α metabolization into a yet-undiscovered pheromone. We further discovered that fish that are insensitive to PGF2α lack an ortholog for the OR Or114 that zebrafish use to detect PGF2α. These results indicate that PGF2α itself does not directly induce male preference in cichlids. Rather, it plays a vital role that primes females to become attractive via an alternative male OR.
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7
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Fiteha YG, Magdy M. The Evolutionary Dynamics of the Mitochondrial tRNA in the Cichlid Fish Family. Biology (Basel) 2022; 11:1522. [PMID: 36290425 DOI: 10.3390/biology11101522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 11/06/2022]
Abstract
Simple Summary Cichlids are a unique example of fish diversity and species richness which have been explained by sympatric speciation at different freshwater sources in Africa. The mitochondria contribute to cell vitality by providing energy. It contains a circular genome with an established translation system that is spatially independent of the cytosolic counterpart. The current study aimed to investigate the evolutionary dynamics of the mitochondrial tRNA and its role in cichlids’ diversity. The available cichlid mitogenomes in the public database were filtered, in addition to newly sequenced accessions from a specific cichlid group known as the haplotilapiine lineage that is widely distributed in the Egyptian sector of the Nile River. Based on the comparative analysis of mitogenomic data, we identified 22 tRNA genes, in which a single gene was D-armless, while the cloverleaf secondary structure subdivided into stem-loop formations was predicted and used to define the levels of genetic divergence for the remained tRNAs. Peculiarly, in cichlids, the formation known as “T-arm” showed the lowest polymorphism levels among other structures in contrast to other organisms (e.g., scorpions). Comparing the whole family to the specific haplotilapiine lineage showed that the tryptophan tRNA was the most conserved tRNA, with signatures of possible purifying selection. Abstract The mitochondrial transfer RNA genes (tRNAs) attract more attention due to their highly dynamic and rapidly evolving nature. The current study aimed to detect and evaluate the dynamics, characteristic patterns, and variations of mitochondrial tRNAs. The study was conducted in two main parts: first, the published mitogenomic sequences of cichlids mt tRNAs have been filtered. Second, the filtered mitochondrial tRNA and additional new mitogenomes representing the most prevalent Egyptian tilapiine were compared and analyzed. Our results revealed that all 22 tRNAs of cichlids folded into a classical cloverleaf secondary structure with four domains, except for trnSGCU, missing the D domain in all cichlids. When consensus tRNAs were compared, most of the mutations were observed in the trnP at nucleotide levels (substitutions and indels), in contrast to trnLUAA. From a structural perspective, the anticodon loop and T-loop formations were the most conserved structures among all parts of the tRNA in contrast to the A-stem and D-loop formations. The trnW was the lowest polymorphic unneutral tRNA among all cichlids (both the family and the haplotilapiine lineage), in contrast with the neutral trnD that was extremely polymorphic among and within the haplotilapiine lineage species compared to other cichlids species. From a phylogenetic perspective, the trnC was extremely hypervariable and neutral tRNA in both haplotilapiine lineage and cichlids but was unable to report correct phylogenetic signal for the cichlids. In contrast to trnI and trnY, less variable neutral tRNAs that were able to cluster the haplotilapiine lineage and cichlids species as previously reported. By observing the DNA polymorphism in the coding DNA sequences (CDS), the highest affected amino acid by non-synonymous mutations was isoleucine and was equally mutated to valine and vice versa; no correlation between mutations in CDS and tRNAs was statistically found. The current study provides an insight into the mitochondrial tRNA evolution and its effect on the cichlid diversity and speciation model at the maternal level.
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Singh P, Irisarri I, Torres-Dowdall J, Thallinger GG, Svardal H, Lemmon EM, Lemmon AR, Koblmüller S, Meyer A, Sturmbauer C. Phylogenomics of trophically diverse cichlids disentangles processes driving adaptive radiation and repeated trophic transitions. Ecol Evol 2022; 12:e9077. [PMID: 35866021 PMCID: PMC9288888 DOI: 10.1002/ece3.9077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/28/2022] [Accepted: 05/31/2022] [Indexed: 11/12/2022] Open
Abstract
Cichlid fishes of the tribe Tropheini are a striking case of adaptive radiation, exemplifying multiple trophic transitions between herbivory and carnivory occurring in sympatry with other established cichlid lineages. Tropheini evolved highly specialized eco-morphologies to exploit similar trophic niches in different ways repeatedly and rapidly. To better understand the evolutionary history and trophic adaptations of this lineage, we generated a dataset of 532 targeted loci from 21 out of the 22 described Tropheini species. We resolved the Tropheini into seven monophyletic genera and discovered one to be polyphyletic. The polyphyletic genus, Petrochromis, represents three convergent origins of the algae grazing trophic specialization. This repeated evolution of grazing may have been facilitated by adaptive introgression as we found evidence for gene flow among algae grazing genera. We also found evidence of gene flow among algae browsing genera, but gene flow was restricted between herbivorous and carnivorous genera. Furthermore, we observed no evidence supporting a hybrid origin of this radiation. Our molecular evolutionary analyses suggest that opsin genes likely evolved in response to selection pressures associated with trophic ecology in the Tropheini. We found surprisingly little evidence of positive selection in coding regions of jaw-shaping genes in this trophically diverse lineage. This suggests low degrees of freedom for further change in these genes, and possibly a larger role for regulatory variation in driving jaw adaptations. Our study emphasizes Tropheini cichlids as an important model for studying the evolution of trophic specialization and its role in speciation.
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Affiliation(s)
- Pooja Singh
- Institute of Biology University of Graz Graz Austria.,Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology University of Konstanz Constance Germany.,Institute of Ecology and Evolution University of Bern Bern Switzerland
| | - Iker Irisarri
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology University of Konstanz Constance Germany.,Leibniz Institute for the Analysis of Biodiversity Change (LIB), Zoological Museum Hamburg Hamburg Germany
| | - Julián Torres-Dowdall
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology University of Konstanz Constance Germany
| | - Gerhard G Thallinger
- Institute of Biomedical Informatics Graz University of Technology Graz Austria.,OMICS Center Graz, BioTechMed Graz Graz Austria
| | - Hannes Svardal
- Department of Biology University of Antwerp Antwerp Belgium.,Naturalis Biodiversity Center Leiden The Netherlands
| | - Emily Moriarty Lemmon
- Department of Biological Science Florida State University, Biomedical Research Facility Tallahassee Florida USA
| | - Alan R Lemmon
- Department of Biological Science Florida State University, Biomedical Research Facility Tallahassee Florida USA
| | | | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology University of Konstanz Constance Germany
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9
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Mehta TK, Penso-Dolfin L, Nash W, Roy S, Di-Palma F, Haerty W. Evolution of miRNA binding sites and regulatory networks in cichlids. Mol Biol Evol 2022; 39:6617238. [PMID: 35748824 PMCID: PMC9260339 DOI: 10.1093/molbev/msac146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The divergence of regulatory regions and gene regulatory network (GRN) rewiring is a key driver of cichlid phenotypic diversity. However, the contribution of miRNA binding site turnover has yet to be linked to GRN evolution across cichlids. Here, we extend our previous studies by analysing the selective constraints driving evolution of miRNA and transcription factor (TF) binding sites of target genes, to infer instances of cichlid GRN rewiring associated with regulatory binding site turnover. Comparative analyses identified increased species-specific networks that are functionally associated to traits of cichlid phenotypic diversity. The evolutionary rewiring is associated with differential models of miRNA and TF binding site turnover, driven by a high proportion of fast-evolving polymorphic sites in adaptive trait genes compared to subsets of random genes. Positive selection acting upon discrete mutations in these regulatory regions is likely to be an important mechanism in rewiring GRNs in rapidly radiating cichlids. Regulatory variants of functionally associated miRNA and TF binding sites of visual opsin genes differentially segregate according to phylogeny and ecology of Lake Malawi species, identifying both rewired e.g. clade-specific and conserved network motifs of adaptive trait associated GRNs. Our approach revealed several novel candidate regulators, regulatory regions and three-node motifs across cichlid genomes with previously reported associations to known adaptive evolutionary traits.
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Affiliation(s)
| | - Luca Penso-Dolfin
- Silence Therapeutics GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | | | - Sushmita Roy
- Dept. of Biostatistics and Medical Informatics, UW Madison, Madison, USA.,Wisconsin Institute for Discovery (WID), Madison, USA.,Dept. of Computer Sciences, UW Madison, Madison, USA
| | - Federica Di-Palma
- School of Biological Sciences, University of East Anglia, Norwich, UK.,Genome British Columbia, Vancouver, Canada
| | - Wilfried Haerty
- Earlham Institute (EI), Norwich, UK.,School of Biological Sciences, University of East Anglia, Norwich, UK
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10
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Reyes-Contreras M, Taborsky B. Stress axis programming generates long-term effects on cognitive abilities in a cooperative breeder. Proc Biol Sci 2022; 289:20220117. [PMID: 35582802 PMCID: PMC9114936 DOI: 10.1098/rspb.2022.0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ability to flexibly adjust behaviour to social and non-social challenges is important for successfully navigating variable environments. Social competence, i.e. adaptive behavioural flexibility in the social domain, allows individuals to optimize their expression of social behaviour. Behavioural flexibility outside the social domain aids in coping with ecological challenges. However, it is unknown if social and non-social behavioural flexibility share common underlying cognitive mechanisms. Support for such shared mechanism would be provided if the same neural mechanisms in the brain affected social and non-social behavioural flexibility similarly. We used individuals of the cooperatively breeding fish Neolamprologus pulcher that had undergone early-life programming of the hypothalamic-pituitary-interrenal axis by exposure to (i) cortisol, (ii) the glucocorticoid receptor antagonist mifepristone, or (iii) control treatments, and where effects of stress-axis programming on social flexibility occurred. One year after the treatments, adults learned a colour discrimination task and subsequently, a reversal-learning task testing for behavioural flexibility. Early-life mifepristone treatment marginally enhanced learning performance, whereas cortisol treatment significantly reduced behavioural flexibility. Thus, early-life cortisol treatment reduced both social and non-social behavioural flexibility, suggesting a shared cognitive basis of behavioural flexibility. Further our findings imply that early-life stress programming affects the ability of organisms to flexibly cope with environmental stressors.
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Affiliation(s)
- Maria Reyes-Contreras
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, CH-3032 Hinterkappelen, Switzerland
| | - Barbara Taborsky
- Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, CH-3032 Hinterkappelen, Switzerland
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11
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Geraerts M, Vangestel C, Artois T, Fernandes JMDO, Jorissen MWP, Chocha Manda A, Danadu Mizani C, Smeets K, Snoeks J, Sonet G, Tingbao Y, Van Steenberge M, Vreven E, Lunkayilakio Wamuini S, Vanhove MPM, Huyse T. Population genomics of introduced Nile tilapia Oreochromis niloticus (Linnaeus, 1758) in the Democratic Republic of the Congo: Repeated introductions since colonial times with multiple sources. Mol Ecol 2022; 31:3304-3322. [PMID: 35460297 DOI: 10.1111/mec.16479] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022]
Abstract
During colonial times, Nile tilapia Oreochromis niloticus (Linnaeus, 1758) was introduced into non-native parts of the Congo Basin (Democratic Republic of the Congo, DRC) for the first time. Currently, it is the most farmed cichlid in the DRC, and is present throughout the Congo Basin. Although Nile tilapia has been reported as an invasive species, documentation of historical introductions into this basin and its consequences are scant. Here, we study the genetic consequences of these introductions by genotyping 213 Nile tilapia from native and introduced regions, focusing on the Congo Basin. Additionally, 48 specimens from 16 other tilapia species were included to test for hybridization. Using RAD sequencing (27,611 single nucleotide polymorphisms), we discovered genetic admixture with other tilapia species in several morphologically identified Nile tilapia from the Congo Basin, reflecting their ability to interbreed and the potential threat they pose to the genetic integrity of native tilapias. Nile tilapia populations from the Upper Congo and those from the Middle-Lower Congo are strongly differentiated. The former show genetic similarity to Nile tilapia from the White Nile, while specimens from the Benue Basin and Lake Kariba are similar to Nile tilapia from the Middle-Lower Congo, suggesting independent introductions using different sources. We conclude that the presence of Nile tilapia in the Congo Basin results from independent introductions, reflecting the dynamic aquaculture history, and that their introduction probably leads to genetic interactions with native tilapias, which could lower their fitness. We therefore urge avoiding further introductions of Nile tilapia in non-native regions and to use native tilapias in future aquaculture efforts.
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Affiliation(s)
- Mare Geraerts
- Research Group Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Carl Vangestel
- OD Taxonomy and Phylogeny, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Terrestrial Ecology Unit, Ghent University, Ghent, Belgium
| | - Tom Artois
- Research Group Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | | | - Michiel W P Jorissen
- Research Group Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Auguste Chocha Manda
- Unité de recherche en Biodiversité et Exploitation durable des Zones Humides (BEZHU), Faculté des Sciences Agronomiques, Université de Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Célestin Danadu Mizani
- Département d'Ecologie et Biodiversité des Ressources Aquatique, Centre de Surveillance de la Biodiversité (CSB), Université de Kisangani, Kisangani, Democratic Republic of the Congo
| | - Karen Smeets
- Research Group Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Jos Snoeks
- Department of Biology, Royal Museum for Central Africa, Tervuren, Belgium.,Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Gontran Sonet
- OD Taxonomy and Phylogeny, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Yang Tingbao
- Institute of Aquatic Economic Animals and Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Zhongshan University, Ghangzhou, China
| | - Maarten Van Steenberge
- OD Taxonomy and Phylogeny, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Emmanuel Vreven
- Department of Biology, Royal Museum for Central Africa, Tervuren, Belgium.,Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Soleil Lunkayilakio Wamuini
- Département de Biologie, I.S.P. Mbanza-Ngungu, Mbanza-Ngungu, Democratic Republic of the Congo.,Functional and Evolutionary Morphology Laboratory, University of Liège, Liège, Belgium
| | - Maarten P M Vanhove
- Research Group Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.,Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium.,Zoology Unit, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tine Huyse
- Department of Biology, Royal Museum for Central Africa, Tervuren, Belgium.,Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
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12
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Bose APH, Dabernig-Heinz J, Koch L, Grimm J, Lang S, Hegedűs B, Banda T, Makasa L, Jordan A, Sefc KM. Parentage analysis across age cohorts reveals sex differences in reproductive skew in a group-living cichlid fish, Neolamprologus multifasciatus. Mol Ecol 2022; 31:2418-2434. [PMID: 35170123 DOI: 10.1111/mec.16401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 11/30/2022]
Abstract
Group-living animals are often faced with complex reproductive decisions, namely how to partition within-group reproduction, how to obtain extra-group reproduction, and how these two means of reproduction should be balanced. The solutions to these questions can be difficult to predict because ecological conditions can affect the scopes for within-group and extra-group reproduction in complex ways. For example, individuals that are restricted from moving freely around their habitats may have limited extra-group reproductive opportunities, but at the same time, groups may live in close proximities to one another, which could potentially have the opposite effect. The group-living cichlid fish, Neolamprologus multifasciatus, experiences such ecological conditions, and we conducted an intensive genetic parentage analysis to investigate how reproduction is distributed within and among groups for both males and females. We found that cohabiting males live in 'high-skew' societies, where dominant males monopolize the majority of within-group reproduction, while females live in 'low-skew' societies, where multiple females can produce offspring concurrently. Despite extremely short distances separating groups, we inferred only very low levels of extra-group reproduction suggesting that subordinate males have very limited reproductive opportunities. A strength of our parentage analysis lies in its inclusion of individuals that spanned a wide age range, from young fry to adults. We outline the logistical circumstances when very young offspring may not always be accessible to parentage researchers, and present strategies to overcome the challenges of inferring mating patterns from a wide age range of offspring.
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Affiliation(s)
- Aneesh P H Bose
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Lukas Koch
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | | | | | | | - Taylor Banda
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, Mpulungu, Zambia
| | - Lawrence Makasa
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, Mpulungu, Zambia
| | - Alex Jordan
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
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13
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Reynolds S, Pierce C, Powell B, Kite A, Hall-Ruiz N, Schilling T, Le Pabic P. A show of Hands: Novel and conserved expression patterns of teleost hand paralogs during craniofacial, heart, fin, peripheral nervous system and gut development. Dev Dyn 2021; 250:1796-1809. [PMID: 34091971 PMCID: PMC8639631 DOI: 10.1002/dvdy.380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/14/2021] [Accepted: 06/03/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Hand genes are required for the development of the vertebrate jaw, heart, peripheral nervous system, limb, gut, placenta, and decidua. Two Hand paralogues, Hand1 and Hand2, are present in most vertebrates, where they mediate different functions yet overlap in expression. In ray-finned fishes, Hand gene expression and function is only known for the zebrafish, which represents the rare condition of having a single Hand gene, hand2. Here we describe the developmental expression of hand1 and hand2 in the cichlid Copadichromis azureus. RESULTS hand1 and hand2 are expressed in the cichlid heart, paired fins, pharyngeal arches, peripheral nervous system, gut, and lateral plate mesoderm with different degrees of overlap. CONCLUSIONS Hand gene expression in the gut, peripheral nervous system, and pharyngeal arches may have already been fixed in the lobe- and ray-finned fish common ancestor. In other embryonic regions, such as paired appendages, hand2 expression was fixed, while hand1 expression diverged in lobe- and ray-finned fish lineages. In the lateral plate mesoderm and arch associated catecholaminergic cells, hand1 and hand2 swapped expression between divergent lineages. Distinct expression of cichlid hand1 and hand2 in the epicardium and myocardium of the developing heart may represent the ancestral pattern for bony fishes.
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Affiliation(s)
- Samantha Reynolds
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Christian Pierce
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Benjamin Powell
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Alexandra Kite
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Nicholas Hall-Ruiz
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Thomas Schilling
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California
| | - Pierre Le Pabic
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
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14
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Gübel J, Bose APH, Jordan A. Social and spatial conflict drive resident aggression toward outsiders in a group-living fish. Behav Ecol 2021; 32:826-834. [PMID: 34690545 PMCID: PMC8528491 DOI: 10.1093/beheco/arab045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/12/2021] [Accepted: 04/22/2021] [Indexed: 11/22/2022] Open
Abstract
Group-living animals often experience within-group competition for resources like shelter and space, as well as for social status. Because of this conflict, residents may aggressively resist joining attempts by new members. Here, we asked whether different forms of competition mediate this response, specifically competition over 1) shelter, 2) spatial position within groups, and 3) social or sexual roles. We performed experiments on wild groups of Neolamprologus multifasciatus cichlids in Lake Tanganyika, either increasing or decreasing the number of shelters (empty snail shells) within their territories. We predicted that increases in resource abundance would reduce conflict and lower the aggression of residents toward presented conspecifics, while decreases in resources would increase aggression. We explored the effects of social conflict and spatial arrangement by introducing same or opposite sex conspecifics, at greater or lesser distances from resident subterritories. We found that changing the abundance of shells had no detectable effect on the responses of residents to presented conspecifics. Rather, aggression was strongly sex-dependent, with male residents almost exclusively aggressing presented males, and female residents almost exclusively aggressing presented females. For females, this aggression was influenced by the spatial distances between the presented conspecific and the resident female subterritory, with aggression scaling with proximity. In contrast, presentation distance did not influence resident males, which were aggressive to all presented males regardless of location. Overall, our results show that group residents respond to presented conspecifics differently depending on the type of competitive threat these potential joiners pose.
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Affiliation(s)
- Jakob Gübel
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany.,Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Aneesh P H Bose
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany.,Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
| | - Alex Jordan
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Universitätsstraße 10, 78464, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany.,Department of Biology, University of Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany
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15
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Tyers AM, Cooke GM, Turner GF. Rare morph Lake Malawi mbuna cichlids benefit from reduced aggression from con- and hetero-specifics. J Evol Biol 2021; 34:1678-1690. [PMID: 34528321 DOI: 10.1111/jeb.13929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/25/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
Balancing selection is important for the maintenance of polymorphism as it can prevent either fixation of one morph through directional selection or genetic drift, or speciation by disruptive selection. Polychromatism, the presence of multiple genetically determined colour phenotypes, can be maintained if the fitness of alternative morphs depends on the relative frequency in a population. In aggressive species, negative frequency-dependent antagonism can prevent an increase in the frequency of rare morphs as they would only benefit from increased fitness while they are rare. Heterospecific aggression is common in nature and has the potential to contribute to rare morph advantage. Here we carry out field observations and laboratory aggression experiments with mbuna cichlids from Lake Malawi, to investigate the role of con- and heterospecific aggression in the maintenance of polychromatism and identify benefits to rare morphs which are likely to result from reduced aggression. We hypothesize that rare morph individuals receive less aggression than common morph individuals and therefore have an ecological advantage. Within species we found that males and females bias aggression towards their own morph, adding to the evidence that inherent own-morph aggression biases can contribute to balancing selection. Over-representation of rare morph territory owners may be influenced by two factors; higher tolerance of different morph individuals as neighbours, and the ability of rare morphs to spend more time feeding. Reduced aggression to rare morph individuals by heterospecifics may also contribute to rare morph advantage.
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Affiliation(s)
| | - Gavan M Cooke
- School of Biological Sciences, Bangor University, Bangor, UK
| | - George F Turner
- School of Biological Sciences, Bangor University, Bangor, UK
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16
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Sowersby W, Cerca J, Wong BBM, Lehtonen TK, Chapple DG, Leal-Cardín M, Barluenga M, Ravinet M. Pervasive admixture and the spread of a large-lipped form in a cichlid fish radiation. Mol Ecol 2021; 30:5551-5571. [PMID: 34418206 DOI: 10.1111/mec.16139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 07/31/2021] [Accepted: 08/11/2021] [Indexed: 12/30/2022]
Abstract
Adaptive radiations have proven important for understanding the mechanisms and processes underlying biological diversity. The convergence of form and function, as well as admixture and adaptive introgression, are common in adaptive radiations. However, distinguishing between these two scenarios remains a challenge for evolutionary research. The Midas cichlid species complex (Amphilophus spp.) is a prime example of adaptive radiation, with phenotypic diversification occurring at various stages of genetic differentiation. One species, A. labiatus, has large fleshy lips, is associated with rocky lake substrates, and occurs patchily within Lakes Nicaragua and Managua. By contrast, the similar, but thin-lipped, congener, A. citrinellus, is more common and widespread. We investigated the evolutionary history of the large-lipped form, specifically regarding whether the trait has evolved independently in both lakes from ancestral thin-lipped populations, or via dispersal and/or admixture events. We collected samples from distinct locations in both lakes, and assessed differences in morphology and ecology. Using RAD-seq, we genotyped thousands of SNPs to measure population structure and divergence, demographic history, and admixture. We found significant between-species differences in ecology and morphology, local intraspecific differences in body shape and trophic traits, but only limited intraspecific variation in lip shape. Despite clear ecological differences, our genomic approach uncovered pervasive admixture between the species and low genomic differentiation, with species within lakes being genetically more similar than species between lakes. Taken together, our results suggest a single origin of large-lips, followed by pervasive admixture and adaptive introgression, with morphology being driven by local ecological opportunities, despite ongoing gene-flow.
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Affiliation(s)
- Will Sowersby
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.,Department of Biology, Osaka City University, Osaka, Japan
| | - José Cerca
- Frontiers of Evolutionary Zoology Research Group, Natural History Museum, University of Oslo, Oslo, Norway.,Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, California, USA.,Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bob B M Wong
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Topi K Lehtonen
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.,Department of Biology, University of Turku, Turku, Finland.,Organismal and Evolutionary Biology, University of Helsinki, Helsinki, Finland
| | - David G Chapple
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Mariana Leal-Cardín
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain.,Universidad de Alcalá de Henares, Madrid, Spain
| | - Marta Barluenga
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Mark Ravinet
- Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway.,Division of Population Genetics, National Institute of Genetics, Mishima, Japan.,School of Life Sciences, University of Nottingham, Nottingham, UK
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17
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Santos-Santos JH, Audenaert L, Verheyen E, Adriaens D. Ontogenetic divergence generates novel phenotypes in hybrid cichlids. J Anat 2021; 238:1116-1127. [PMID: 33417249 PMCID: PMC8053579 DOI: 10.1111/joa.13375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022] Open
Abstract
Hybridization is suggested to contribute to ecomorphological and taxonomic diversity in lacustrine East African cichlids. This is supported by studies demonstrating that genetic diversity within lake radiations has been influenced by hybridization events, leading to extensive phenotypic differentiation of genetically closely related species. Hybrid persistence and speciation in sympatry with gene flow can be explained by pleiotropy in traits involved in reproductive isolation; however, little attention has been given to how trait differentiation is established during hybrid ontogeny, and how this may relate to trophic and locomotor specialization. This study compares body shape changes in a Lake Victoria cichlid hybrid throughout its post-hatch ontogeny to those of its parental species. Across the considered age/size categories, hybrids occupy a distinct and intermediate morphological space, yet where several transgressive traits emerge. A between-group principal component analysis on body shapes across size categories reveals axes of shape variation exclusive to the hybrids in the youngest/smallest size categories. Shape differences in the hybrids involved morphological traits known to be implicated in trophic and locomotor specializations in the parental species. Combined, our findings suggest that phenotypic divergence in the hybrid can lead to functional differences that may potentially release them to some degree from competition with the parental species. These findings agree with recent literature that addresses the potential importance of hybridization for the unusually recent origin of the Lake Victoria cichlid super-species flock.
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Affiliation(s)
- Javier H Santos-Santos
- Evolutionary Morphology of Vertebrates, Ghent University, Gent, Belgium.,Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas (MNCN-CSIC), Madrid, Spain
| | - Leen Audenaert
- OD Taxonomy and Phylogeny, Vertebrates, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Erik Verheyen
- OD Taxonomy and Phylogeny, Vertebrates, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Evolutionary Ecology Group, Biology Department, University of Antwerp, Antwerp, Belgium
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18
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Rajkov J, El Taher A, Böhne A, Salzburger W, Egger B. Gene expression remodelling and immune response during adaptive divergence in an African cichlid fish. Mol Ecol 2020; 30:274-296. [PMID: 33107988 DOI: 10.1111/mec.15709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/08/2020] [Accepted: 10/19/2020] [Indexed: 11/29/2022]
Abstract
Variation in gene expression contributes to ecological speciation by facilitating population persistence in novel environments. Likewise, immune responses can be of relevance in speciation driven by adaptation to different environments. Previous studies examining gene expression differences between recently diverged ecotypes have often relied on only one pair of populations, targeted the expression of only a subset of genes or used wild-caught individuals. Here, we investigated the contribution of habitat-specific parasites and symbionts and the underlying immunological abilities of ecotype hosts to adaptive divergence in lake-river population pairs of the cichlid fish Astatotilapia burtoni. To shed light on the role of phenotypic plasticity in adaptive divergence, we compared parasite and microbiota communities, immune response, and gene expression patterns of fish from natural habitats and a lake-like pond set-up. In all investigated population pairs, lake fish were more heavily parasitized than river fish, in terms of both parasite taxon composition and infection abundance. The innate immune response in the wild was higher in lake than in river populations and was elevated in a river population exposed to lake parasites in the pond set-up. Environmental differences between lake and river habitat and their distinct parasite communities have shaped differential gene expression, involving genes functioning in osmoregulation and immune response. Most changes in gene expression between lake and river samples in the wild and in the pond set-up were based on a plastic response. Finally, gene expression and bacterial communities of wild-caught individuals and individuals acclimatized to lake-like pond conditions showed shifts underlying adaptive phenotypic plasticity.
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Affiliation(s)
- Jelena Rajkov
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Athimed El Taher
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Astrid Böhne
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Walter Salzburger
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Bernd Egger
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
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19
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Sandkam BA, Campello L, O’Brien C, Nandamuri SP, Gammerdinger WJ, Conte MA, Swaroop A, Carleton KL. Tbx2a Modulates Switching of RH2 and LWS Opsin Gene Expression. Mol Biol Evol 2020; 37:2002-2014. [PMID: 32191319 PMCID: PMC7849988 DOI: 10.1093/molbev/msaa062] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sensory systems are tuned by selection to maximize organismal fitness in particular environments. This tuning has implications for intraspecies communication, the maintenance of species boundaries, and speciation. Tuning of color vision largely depends on the sequence of the expressed opsin proteins. To improve tuning of visual sensitivities to shifts in habitat or foraging ecology over the course of development, many organisms change which opsins are expressed. Changes in this developmental sequence (heterochronic shifts) can create differences in visual sensitivity among closely related species. The genetic mechanisms by which these developmental shifts occur are poorly understood. Here, we use quantitative trait locus analyses, genome sequencing, and gene expression studies in African cichlid fishes to identify a role for the transcription factor Tbx2a in driving a switch between long wavelength sensitive (LWS) and Rhodopsin-like (RH2) opsin expression. We identify binding sites for Tbx2a in the LWS promoter and the highly conserved locus control region of RH2 which concurrently promote LWS expression while repressing RH2 expression. We also present evidence that a single change in Tbx2a regulatory sequence has led to a species difference in visual tuning, providing the first mechanistic model for the evolution of rapid switches in sensory tuning. This difference in visual tuning likely has important roles in evolution as it corresponds to differences in diet, microhabitat choice, and male nuptial coloration.
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Affiliation(s)
| | - Laura Campello
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Conor O’Brien
- Department of Biology, University of Maryland, College Park, MD
| | | | | | - Matthew A Conte
- Department of Biology, University of Maryland, College Park, MD
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD
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20
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Bose APH, Windorfer J, Böhm A, Ronco F, Indermaur A, Salzburger W, Jordan A. Structural manipulations of a shelter resource reveal underlying preference functions in a shell-dwelling cichlid fish. Proc Biol Sci 2020; 287:20200127. [PMID: 32429812 PMCID: PMC7287357 DOI: 10.1098/rspb.2020.0127] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many animals can modify the environments in which they live, thereby changing the selection pressures they experience. A common example of such niche construction is the use, creation or modification of environmental resources for use as nests or shelters. Because these resources often have correlated structural elements, it can be difficult to disentangle the relative contribution of these elements to resource choice, and the preference functions underlying niche-construction behaviour remain hidden. Here, we present an experimental paradigm that uses 3D scanning, modelling and printing to create replicas of structures that differ with respect to key structural attributes. We show that a niche-constructing, shell-dwelling cichlid fish, Neolamprologus multifasciatus, has strong open-ended preference functions for exaggerated shell replicas. Fish preferred shells that were fully intact and either enlarged, lengthened or had widened apertures. Shell intactness was the most important structural attribute, followed by shell length, then aperture width. We disentangle the relative roles of different shell attributes, which are tightly correlated in the wild, but nevertheless differentially influence shelter choice and therefore niche construction in this species. We highlight the broad utility of our approach when compared with more traditional methods (e.g. two-choice tasks) for studying animal decision-making in a range of contexts.
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Affiliation(s)
- Aneesh P H Bose
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Johannes Windorfer
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Alex Böhm
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Fabrizia Ronco
- Zoological Institute, University of Basel, Basel, Switzerland
| | | | | | - Alex Jordan
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Faber-Hammond JJ, Bezault E, Lunt DH, Joyce DA, Renn SCP. The Genomic Substrate for Adaptive Radiation: Copy Number Variation across 12 Tribes of African Cichlid Species. Genome Biol Evol 2020; 11:2856-2874. [PMID: 31504491 DOI: 10.1093/gbe/evz185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2019] [Indexed: 02/06/2023] Open
Abstract
The initial sequencing of five cichlid genomes revealed an accumulation of genetic variation, including extensive copy number variation in cichlid lineages particularly those that have undergone dramatic evolutionary radiation. Gene duplication has the potential to generate substantial molecular substrate for the origin of evolutionary novelty. We use array-based comparative heterologous genomic hybridization to identify copy number variation events (CNVEs) for 168 samples representing 53 cichlid species including the 5 species for which full genome sequence is available. We identify an average of 50-100 CNVEs per individual. For those species represented by multiple samples, we identify 150-200 total CNVEs suggesting a substantial amount of intraspecific variation. For these species, only ∼10% of the detected CNVEs are fixed. Hierarchical clustering of species according to CNVE data recapitulates phylogenetic relationships fairly well at both the tribe and radiation level. Although CNVEs are detected on all linkage groups, they tend to cluster in "hotspots" and are likely to contain and be flanked by transposable elements. Furthermore, we show that CNVEs impact functional categories of genes with potential roles in adaptive phenotypes that could reasonably promote divergence and speciation in the cichlid clade. These data contribute to a more complete understanding of the molecular basis for adaptive natural selection, speciation, and evolutionary radiation.
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Affiliation(s)
| | - Etienne Bezault
- BOREA Research Unit, MNHN, CNRS 7208, Sorbonne Université, IRD 207, UCN, UA, Paris, France
| | - David H Lunt
- Department of Biological and Marine Sciences, University of Hull, Hull Kingston-Upon-Hull, United Kingdom
| | - Domino A Joyce
- Department of Biological and Marine Sciences, University of Hull, Hull Kingston-Upon-Hull, United Kingdom
| | - Suzy C P Renn
- Department of Biology, Reed College, Portland OR 97202
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23
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Ogawa S, Parhar I. Morphological Evidence for Functional Crosstalk Between Multiple GnRH Systems in the Male Tilapia, Oreochromis niloticus. Front Endocrinol (Lausanne) 2020; 11:586. [PMID: 32982977 PMCID: PMC7492274 DOI: 10.3389/fendo.2020.00586] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/17/2020] [Indexed: 12/18/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is a reproductive neuropeptide, which controls vertebrate reproduction. In most vertebrates, there are more than two GnRH orthologs in the brain. In cichlid fish, the Nile tilapia (Oreochromis niloticus), GnRH1 is the primary hypophysiotropic hormone, while GnRH2 and GnRH3 are non-hypophysiotropic but neuromodulatory in function. Hypophysiotropic GnRH neurons are thought to inter-communicate, while it remains unknown if hypophysiotropic and non-hypophysiotropic GnRH systems communicate with each other. In the present study, we examined interrelationship between three GnRH types using specific antibodies raised against their respective GnRH associated peptide (GAP) sequence. Double-immunofluorescence labeling coupled with confocal microscopy revealed that in sexually mature males, GnRH-GAP1-immunoreactive (-ir) processes are in proximities of GnRH-GAP3-ir cell somata in the terminal nerve, while GnRH-GAP1-ir cell somata were also accompanied by GnRH-GAP3-ir processes in the preoptic area. However, such interaction was not seen in immature males. Further, there was no interaction between GnRH-GAP2 and GnRH-GAP1 or GnRH-GAP3 neurons. Single cell gene expression analysis revealed co-expression of multiple GnRH receptor genes (gnrhr1 and gnrhr2) in three GnRH-GAP cell types. In mature males, high levels of gnrhr2 mRNA were expressed in GnRH-GAP1-ir cells. In immature males, gnrhr1 and gnrhr2 mRNAs are highly expressed in GnRH-GAP3-ir cells. These results suggest heterologous interactions between the three GnRH-GAP cell types and their potential functional interaction during different reproductive stages.
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24
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Bose APH, Zimmermann H, Sefc KM. Freshwater hydrozoan blooms alter activity and behaviour of territorial cichlids in Lake Tanganyika. R Soc Open Sci 2019; 6:191053. [PMID: 31827845 PMCID: PMC6894582 DOI: 10.1098/rsos.191053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Blooms of gelatinous zooplankton can represent dramatic environmental perturbations for aquatic ecosystems. Yet, we still know little about how blooms impact fitness-related behaviours of fish caught within their areas of effect, especially for freshwater systems. Here, we documented the behavioural impacts of freshwater hydrozoan (Limnocnida tanganjicae) blooms on a territorial cichlid (Variabilichromis moorii), as well as on the wider community of cichlids in a shallow-water rocky habitat of Lake Tanganyika. Compared with non-bloom conditions, V. moorii individuals in the midst of blooms reduced their swimming and territory defence activities (each by approx. 50%) but not their foraging or affiliative behaviours. Despite this reduction in activity, V. moorii could not entirely avoid being stung and preferred to remain closer to the rocky substrata as opposed to the more open demersal zone. Many other fishes similarly hid among the benthic substrata, changing the composition of the fish community in the demersal zone during bloom conditions. Reductions in activity could have multiple fitness-related implications for individual fish. Establishing the consequences of these behavioural changes is important for understanding the effects of gelatinous zooplankton blooms in freshwater systems.
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25
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Yourick MR, Sandkam BA, Gammerdinger WJ, Escobar-Camacho D, Nandamuri SP, Clark FE, Joyce B, Conte MA, Kocher TD, Carleton KL. Diurnal variation in opsin expression and common housekeeping genes necessitates comprehensive normalization methods for quantitative real-time PCR analyses. Mol Ecol Resour 2019; 19:1447-1460. [PMID: 31325910 DOI: 10.1111/1755-0998.13062] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/17/2019] [Accepted: 06/24/2019] [Indexed: 01/03/2023]
Abstract
To determine the visual sensitivities of an organism of interest, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is often used to quantify expression of the light-sensitive opsins in the retina. While qRT-PCR is an affordable, high-throughput method for measuring expression, it comes with inherent normalization issues that affect the interpretation of results, especially as opsin expression can vary greatly based on developmental stage, light environment or diurnal cycles. We tested for diurnal cycles of opsin expression over a period of 24 hr at 1-hr increments and examined how normalization affects a data set with fluctuating expression levels using qRT-PCR and transcriptome data from the retinae of the cichlid Pelmatolapia mariae. We compared five methods of normalizing opsin expression relative to (a) the average of three stably expressed housekeeping genes (Ube2z, EF1-α and β-actin), (b) total RNA concentration, (c) GNAT2, (the cone-specific subunit of transducin), (d) total opsin expression and (e) only opsins expressed in the same cone type. Normalizing by proportion of cone type produced the least variation and would be best for removing time-of-day variation. In contrast, normalizing by housekeeping genes produced the highest daily variation in expression and demonstrated that the peak of cone opsin expression was in the late afternoon. A weighted correlation network analysis showed that the expression of different cone opsins follows a very similar daily cycle. With the knowledge of how these normalization methods affect opsin expression data, we make recommendations for designing sampling approaches and quantification methods based upon the scientific question being examined.
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Affiliation(s)
- Miranda R Yourick
- Department of Biology, University of Maryland, College Park, Maryland
| | | | | | | | | | - Frances E Clark
- Department of Biology, University of Maryland, College Park, Maryland
| | - Brendan Joyce
- Department of Biology, University of Maryland, College Park, Maryland
| | - Matthew A Conte
- Department of Biology, University of Maryland, College Park, Maryland
| | - Thomas D Kocher
- Department of Biology, University of Maryland, College Park, Maryland
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, Maryland
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26
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Burress ED, Piálek L, Casciotta JR, Almirón A, Tan M, Armbruster JW, Říčan O. Island- and lake-like parallel adaptive radiations replicated in rivers. Proc Biol Sci 2019; 285:rspb.2017.1762. [PMID: 29298932 DOI: 10.1098/rspb.2017.1762] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 11/29/2017] [Indexed: 11/12/2022] Open
Abstract
Parallel adaptive radiations have arisen following the colonization of islands by lizards and lakes by fishes. In these classic examples, parallel adaptive radiation is a response to the ecological opportunities afforded by the colonization of novel ecosystems and similar adaptive landscapes that favour the evolution of similar suites of ecomorphs, despite independent evolutionary histories. Here, we demonstrate that parallel adaptive radiations of cichlid fishes arose in South American rivers. Speciation-assembled communities of pike cichlids (Crenicichla) have independently diversified into similar suites of novel ecomorphs in the Uruguay and Paraná Rivers, including crevice feeders, periphyton grazers and molluscivores. There were bursts in phenotypic evolution associated with the colonization of each river and the subsequent expansion of morphospace following the evolution of the ecomorphs. These riverine clades demonstrate that characteristics emblematic of textbook parallel adaptive radiations of island- and lake-dwelling assemblages are feasible evolutionary outcomes even in labile ecosystems such as rivers.
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Affiliation(s)
- Edward D Burress
- Department of Biological Sciences and Auburn University Museum of Natural History, Auburn University, Auburn, AL, USA
| | - Lubomír Piálek
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Jorge R Casciotta
- División Zoologia Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina.,Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Buenos Aires, Argentina
| | - Adriana Almirón
- División Zoologia Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina
| | - Milton Tan
- Department of Biological Sciences and Auburn University Museum of Natural History, Auburn University, Auburn, AL, USA
| | - Jonathan W Armbruster
- Department of Biological Sciences and Auburn University Museum of Natural History, Auburn University, Auburn, AL, USA
| | - Oldřich Říčan
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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27
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Conith AJ, Lam DT, Albertson RC. Muscle-induced loading as an important source of variation in craniofacial skeletal shape. Genesis 2018; 57:e23263. [PMID: 30418689 DOI: 10.1002/dvg.23263] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/25/2018] [Accepted: 10/27/2018] [Indexed: 01/01/2023]
Abstract
The shape of the craniofacial skeleton is constantly changing through ontogeny and reflects a balance between developmental patterning and mechanical-load-induced remodeling. Muscles are a major contributor to producing the mechanical environment that is crucial for "normal" skull development. Here, we use an F5 hybrid population of Lake Malawi cichlids to characterize the strength and types of associations between craniofacial bones and muscles. We focus on four bones/bone complexes, with different developmental origins, alongside four muscles with distinct functions. We used micro-computed tomography to extract 3D information on bones and muscles. 3D geometric morphometrics and volumetric measurements were used to characterize bone and muscle shape, respectively. Linear regressions were performed to test for associations between bone shape and muscle volume. We identified three types of associations between muscles and bones: weak, strong direct (i.e., muscles insert directly onto bone), and strong indirect (i.e., bone is influenced by muscles without a direct connection). In addition, we show that although the shape of some bones is relatively robust to muscle-induced mechanical stimulus, others appear to be highly sensitive to muscular input. Our results imply that the roles for muscular input on skeletal shape extend beyond specific points of origin or insertion and hold significant potential to influence broader patterns of craniofacial geometry. Thus, changes in the loading environment, either as a normal course of ontogeny or if an organism is exposed to a novel environment, may have pronounced effects on skeletal shape via near and far-ranging effects of muscular loading.
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Affiliation(s)
- Andrew J Conith
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Daniel T Lam
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
| | - R Craig Albertson
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
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28
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Harding HR, Gordon TAC, Hsuan RE, Mackaness ACE, Radford AN, Simpson SD. Fish in habitats with higher motorboat disturbance show reduced sensitivity to motorboat noise. Biol Lett 2018; 14:20180441. [PMID: 30282747 PMCID: PMC6227867 DOI: 10.1098/rsbl.2018.0441] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/05/2018] [Indexed: 11/12/2022] Open
Abstract
Anthropogenic noise can negatively impact many taxa worldwide. It is possible that in noisy, high-disturbance environments, the range and severity of impacts could diminish over time, but the influence of previous disturbance remains untested in natural conditions. This study demonstrates the effects of motorboat noise on the physiology of an endemic cichlid fish in Lake Malawi. Exposure to motorboats (driven 20-100 m from fish) and loudspeaker playback of motorboat noise both elevated the oxygen-consumption rate at a single lower-disturbance site, characterized by low historic and current motorboat activity. Repeating this assay at further lower-disturbance sites revealed a consistent effect of elevated oxygen consumption in response to motorboat disturbance. However, when similar trials were repeated at four higher-disturbance sites, no effect of motorboat exposure was detected. These results demonstrate that disturbance history can affect local population responses to noise. Action regarding noise pollution should consider the past, as well as the present, when planning for the future.
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Affiliation(s)
- Harry R Harding
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- Marine Scotland Science, 375 Victoria Road, Aberdeen AB11 9DB, UK
| | - Timothy A C Gordon
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Rachel E Hsuan
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Alex C E Mackaness
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Andrew N Radford
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Stephen D Simpson
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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29
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Bose APH, Zimmermann H, Henshaw JM, Fritzsche K, Sefc KM. Brood-tending males in a biparental fish suffer high paternity losses but rarely cuckold. Mol Ecol 2018; 27:4309-4321. [PMID: 30182504 PMCID: PMC6221093 DOI: 10.1111/mec.14857] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/13/2018] [Accepted: 08/29/2018] [Indexed: 12/25/2022]
Abstract
Extra‐pair paternity within socially monogamous mating systems is well studied in birds and mammals but rather neglected in other animal taxa. In fishes, social monogamy has evolved several times but few studies have investigated the extent to which pair‐bonded male fish lose fertilizations to cuckolders and gain extra‐pair fertilizations themselves. We address this gap and present genetic paternity data collected from a wild population of Variabilichromis moorii, a socially monogamous African cichlid with biparental care of offspring. We show that brood‐tending, pair‐bonded males suffer exceptionally high paternity losses, siring only 63% of the offspring produced by their female partners on average. The number of cuckolders per brood ranged up to nine and yet, surprisingly, brood‐tending males in the population were rarely the culprits. Brood‐tending males sired very few extra‐pair offspring, despite breeding in close proximity to one another. While unpaired males were largely responsible for the cuckoldry, pair‐bonded males still enjoyed higher fertilization success than individual unpaired males. We discuss these results in the context of ecological and phenotypic constraints on cuckoldry and the fitness payoffs of alternative male tactics. Our study provides new insights into how pair‐bonded males handle the trade‐off between securing within‐pair and extra‐pair reproduction.
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Abstract
Most biomedical research is performed using a very limited number of "model" species. In part, this has resulted from a combination of full genomes, manipulation of genes, and short generation times in these species. However, the advent of low-cost sequencing and gene editing in any organism has increased the use of nontraditional organisms. Many scientists have paraphrased the adage by Krogh [ Krogh , A. ( 2018 ) Science 70 , 200 - 204 ] that for many biological problems some species will prove to be most convenient and useful to study. In particular, using organisms most suited to the specific research question can lead to novel insights about fundamental physiological, neurobiological, immunological, and neuroendocrine systems that can advance our understanding of the well-being and health of humans. In addition, such studies have led to new ideas about the evolution and mechanisms that control social behavior. Fishes constitute about 50% of all vertebrate species and are the most diverse vertebrate radiation. Here we review behavioral and neurobiological discoveries of plasticity in social behavior resulting from analysis of an African cichlid fish, showing how its unique behavioral system has facilitated a broad range of discoveries. For many future questions, Astatotilapia burtoni and other cichlid fishes may be ideally suited to study as we advance our understanding of the neural basis of social decisions.
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Affiliation(s)
- Karen P. Maruska
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Russell D. Fernald
- Biology Department, Stanford University, Stanford, California 94305, United States
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31
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Rajkov J, Weber AA, Salzburger W, Egger B. Adaptive phenotypic plasticity contributes to divergence between lake and river populations of an East African cichlid fish. Ecol Evol 2018; 8:7323-7333. [PMID: 30151152 PMCID: PMC6106192 DOI: 10.1002/ece3.4241] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 01/01/2023] Open
Abstract
Adaptive phenotypic plasticity and fixed genotypic differences have long been considered opposing strategies in adaptation. More recently, these mechanisms have been proposed to act complementarily and under certain conditions jointly facilitate evolution, speciation, and even adaptive radiations. Here, we investigate the relative contributions of adaptive phenotypic plasticity vs. local adaptation to fitness, using an emerging model system to study early phases of adaptive divergence, the generalist cichlid fish species Astatotilapia burtoni. We tested direct fitness consequences of morphological divergence between lake and river populations in nature by performing two transplant experiments in Lake Tanganyika. In the first experiment, we used wild-caught juvenile lake and river individuals, while in the second experiment, we used F1 crosses between lake and river fish bred in a common garden setup. By tracking the survival and growth of translocated individuals in enclosures in the lake over several weeks, we revealed local adaptation evidenced by faster growth of the wild-caught resident population in the first experiment. On the other hand, we did not find difference in growth between different types of F1 crosses in the second experiment, suggesting a substantial contribution of adaptive phenotypic plasticity to increased immigrant fitness. Our findings highlight the value of formally comparing fitness of wild-caught and common garden-reared individuals and emphasize the necessity of considering adaptive phenotypic plasticity in the study of adaptive divergence.
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Affiliation(s)
- Jelena Rajkov
- Zoological InstituteUniversity of BaselBaselSwitzerland
| | | | | | - Bernd Egger
- Zoological InstituteUniversity of BaselBaselSwitzerland
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32
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Ugwu SI, Shiba K, Inaba K, Morita M. A Unique Seminal Plasma Protein, Zona Pellucida 3-Like Protein, has Ca 2+ -Dependent Sperm Agglutination Activity. Zoolog Sci 2018; 35:161-171. [PMID: 29623792 DOI: 10.2108/zs170150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Identification of seminal proteins provides a means of investigating their roles. Despite their importance in the study of protein function, such as regulation of sperm motility, it is difficult to select candidates from the large number of proteins. Analyzing the rate of molecular evolution is a useful strategy for selecting candidates, and expressing the protein allows the examination of its function. In the present study, we investigated seminal plasma proteins of the cichlid Oreochromis mossambicus, which exhibits a unique mode of fertilization and a rapidly evolving gene that encodes a seminal plasma protein, zona-pellucida 3-like (ZP3-like), which does not belong to the same molecular family as other ZPs. Seminal plasma proteins of O. mossambicus were separated by two-dimensional electrophoresis, and 19 major proteins were identified by mass spectrometry (MALDI-Tof Mass). Because proteins that are under positive selection often impact sperm function, the rates of molecular evolution of these proteins were analyzed in terms of non-synonymous/synonymous substitutions (ω). Among the 19 proteins, positive selection was supported for five genes; functional assays were carried out on four of the proteins encoded by these genes. Of the four positively selected proteins, only ZP3-like protein agglutinated sperm in a dose- and Ca2+ -dependent manner. The other three proteins did not affect sperm motility. Because of the unique fertilization type, in which fertilization occurs in the buccal cavity, the need to retain sperm within the cavity during spawning, and the agglutination of sperm, which may be partly assisted by ZP3-like protein, may contribute to fertilization success. Fertilization in the buccal cavity may be related to its rapid molecular evolution.
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Affiliation(s)
- Stanley Ifeanyi Ugwu
- 1 Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan
| | - Kogiku Shiba
- 2 Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda City, Shizuoka 415-0025, Japan
| | - Kazuo Inaba
- 2 Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda City, Shizuoka 415-0025, Japan
| | - Masaya Morita
- 1 Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan
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33
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Yeh SW, Cheng YH, Nan FN, Wen CM. Characterization and virus susceptibility of a continuous cell line derived from the brain of Aequidens rivulatus (Günther). J Fish Dis 2018; 41:635-641. [PMID: 29399816 DOI: 10.1111/jfd.12763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/10/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
Cell cultures derived from the brain tissues of Aequidens rivulatus (Günther) have been characterized previously. In this study, a continuous cell line ARB8 was further established, and its growth characteristics, transcription and susceptibility to fish viruses-including chum salmon reovirus (CSV), marbled eel infectious pancreative necrosis virus (MEIPNV), grouper nervous necrosis virus (GNNV), giant seaperch iridovirus (GSIV), red seabream iridovirus (RSIV), koi herpesvirus (KHV), herpesvirus anguilla (HVA) and marbled eel polyoma-like virus (MEPyV)-were examined. ARB8 cells that showed epithelioid morphology and were passaged >80 times grew well at temperatures ranging from 25°C to 30°C in L-15 medium containing 5%-15% foetal bovine serum. The cells constitutively transcribed connexion 43, glutamine synthetase, nestin and nkx6-2, which are markers for neural progenitor cells. The cells were highly susceptible to CSV, MEIPNV, GSIV and RSIV and showed the typical cytopathic effect (CPE). However, the cells were resistant to GNNV, KHV, HVA and MEPyV because no significant CPE was noted after infection. Optimal temperatures for virus production ranged from 25°C to 30°C. The results revealed that the neural progenitor cell line ARB8 can potentially serve as a useful tool for investigating fish viruses and isolating new viruses in ornamental cichlid fishes.
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Affiliation(s)
- S W Yeh
- Department of Life Sciences, National University of Kaohsiung, Kaohsiung, Taiwan
| | - Y H Cheng
- Department of Biotechnology and Animal Science, National Ilan University, Ilan, Taiwan
| | - F N Nan
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan
| | - C M Wen
- Department of Life Sciences, National University of Kaohsiung, Kaohsiung, Taiwan
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34
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Kasper C, Kölliker M, Postma E, Taborsky B. Consistent cooperation in a cichlid fish is caused by maternal and developmental effects rather than heritable genetic variation. Proc Biol Sci 2018; 284:rspb.2017.0369. [PMID: 28701555 DOI: 10.1098/rspb.2017.0369] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/05/2017] [Indexed: 01/29/2023] Open
Abstract
Studies on the evolution of cooperative behaviour are typically confined to understanding its adaptive value. It is equally essential, however, to understand its potential to evolve, requiring knowledge about the phenotypic consistency and genetic basis of cooperative behaviour. While previous observational studies reported considerably high heritabilities of helping behaviour in cooperatively breeding vertebrates, experimental studies disentangling the relevant genetic and non-genetic components of cooperative behaviour are lacking. In a half-sibling breeding experiment, we investigated the repeatability and heritability of three major helping behaviours performed by subordinates of the cooperatively breeding fish Neolamprologus pulcher To experimentally manipulate the amount of help needed in a territory, we raised the fish in two environments differing in egg predation risk. All three helping behaviours were significantly repeatable, but had very low heritabilities. The high within-individual consistencies were predominantly due to maternal and permanent environment effects. The perceived egg predation risk had no effect on helping, but social interactions significantly influenced helping propensities. Our results reveal that developmentally plastic adjustments of provided help to social context shape cooperative phenotypes, whereas heritable genetic variation plays a minor role.
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Affiliation(s)
- Claudia Kasper
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland
| | - Mathias Kölliker
- Institute of Evolutionary Biology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Erik Postma
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.,Center for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE
| | - Barbara Taborsky
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50A, 3032 Hinterkappelen, Switzerland
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35
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Ito MH, Yamaguchi M, Kutsukake N. Redirected aggression as a conflict management tactic in the social cichlid fish Julidochromis regani. Proc Biol Sci 2018; 285:20172681. [PMID: 29386369 PMCID: PMC5805954 DOI: 10.1098/rspb.2017.2681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/10/2018] [Indexed: 11/12/2022] Open
Abstract
Conflict management consists of social behaviours that reduce the costs of conflict among group members. Redirected aggression-that is, when a recently attacked individual attacks a third party immediately after the original aggression-is considered a conflict management tactic, as it may reduce the victim's probability of being the object of further aggression. Redirected aggression has been reported in many vertebrates, but few quantitative studies have been conducted on this behaviour in fishes. We examined the function of redirected aggression in Julidochromis regani, a social cichlid fish. Behavioural experiments showed that redirected aggression functioned to divert the original aggressor's attention towards a third party and to pre-empt an attack towards the victim by the third-party individual, specifically among females. We found, however, that redirected aggression did not delay the recurrence of aggression by the original aggressor. These results suggest that a primary function of redirected aggression is to maintain the dominance of its actor against a subordinate occupying an adjacent rank. This study provides, to our knowledge, the first evidence that redirected aggression functions to manage conflict in social fish.
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Affiliation(s)
- Munehiko H Ito
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Miura, Kanagawa 240-0193, Japan
| | - Motoomi Yamaguchi
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Miura, Kanagawa 240-0193, Japan
| | - Nobuyuki Kutsukake
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Miura, Kanagawa 240-0193, Japan
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36
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Bachmann JC, Cortesi F, Hall MD, Marshall NJ, Salzburger W, Gante HF. Real-time social selection maintains honesty of a dynamic visual signal in cooperative fish. Evol Lett 2017; 1:269-278. [PMID: 30283655 PMCID: PMC6121853 DOI: 10.1002/evl3.24] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/21/2017] [Accepted: 09/01/2017] [Indexed: 01/04/2023] Open
Abstract
Our understanding of animal communication has been largely driven by advances in theory since empirical evidence has been difficult to obtain. Costly signaling theory became the dominant paradigm explaining the evolution of honest signals, according to which communication reliability relies on differential costs imposed on signalers to distinguish animals of different quality. On the other hand, mathematical models disagree on the source of costs at the communication equilibrium. Here, we present an empirical framework to study the evolution of honest signals that generates predictions on the form, function, and sources of reliability of visual signals. We test these predictions on the facial color patterns of the cooperatively breeding Princess of Burundi cichlid, Neolamprologus brichardi. Using theoretical visual models and behavioral experiments we show that these patterns possess stable chromatic properties for efficient transmission in the aquatic environment, while dynamic changes in signal luminance are used by the fish to communicate switches in aggressive intent. By manipulating signal into out-of-equilibrium expression and simulating a cheater invasion, we demonstrate that social costs (receiver retaliation) promote the honesty of this dynamic conventional signal. By directly probing the sender of a signal in real time, social selection is likely to be the mechanism of choice shaping the evolution of inexpensive, yet reliable context-dependent social signals in general.
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Affiliation(s)
- Judith C Bachmann
- Zoological Institute, Vesalgasse 1 University of Basel 4051 Basel Switzerland.,Department of Evolutionary Biology and Environmental Studies University of Zurich 8057 Zurich Switzerland
| | - Fabio Cortesi
- Zoological Institute, Vesalgasse 1 University of Basel 4051 Basel Switzerland.,Queensland Brain Institute University of Queensland Brisbane Queensland 4072 Australia
| | - Matthew D Hall
- School of Biological Sciences Monash University Melbourne 3800 Australia
| | - N Justin Marshall
- Queensland Brain Institute University of Queensland Brisbane Queensland 4072 Australia
| | - Walter Salzburger
- Zoological Institute, Vesalgasse 1 University of Basel 4051 Basel Switzerland
| | - Hugo F Gante
- Zoological Institute, Vesalgasse 1 University of Basel 4051 Basel Switzerland
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37
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Nandamuri SP, Yourick MR, Carleton KL. Adult plasticity in African cichlids: Rapid changes in opsin expression in response to environmental light differences. Mol Ecol 2017; 26:6036-6052. [PMID: 28926160 DOI: 10.1111/mec.14357] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/01/2017] [Accepted: 08/14/2017] [Indexed: 01/09/2023]
Abstract
Phenotypic plasticity allows organisms to adapt quickly to local environmental conditions and could facilitate adaptive radiations. Cichlids have recently undergone an adaptive radiation in Lake Malawi where they inhabit diverse light environments and tune their visual sensitivity through differences in cone opsin expression. While cichlid opsin expression is known to be plastic over development, whether adults remain plastic is unknown. Adult plasticity in visual tuning could play a role in cichlid radiations by enabling survival in changing environments and facilitating invasion into novel environments. Here we examine the existence of and temporal changes in adult visual plasticity of two closely related species. In complementary experiments, wild adult Metriaclima mbenji from Lake Malawi were moved to the lab under UV-deficient fluorescent lighting; while lab raised M. benetos were placed under UV-rich lighting designed to mimic light conditions in the wild. Surprisingly, adult cichlids in both experiments showed significant changes in the expression of the UV-sensitive single cone opsin, SWS1, in only 3 days. Modeling quantum catches in the light environments revealed a possible link between the light available to the SWS1 visual pigment and SWS1 expression. We conclude that adult cichlids can undergo rapid and significant changes in opsin expression in response to environmental light shifts that are relevant to their habitat and evolutionary history in Lake Malawi. This could have contributed to the rapid divergence characteristic of these fantastic fishes.
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Affiliation(s)
| | - Miranda R Yourick
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD, USA
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38
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Hahn C, Genner MJ, Turner GF, Joyce DA. The genomic basis of cichlid fish adaptation within the deepwater "twilight zone" of Lake Malawi. Evol Lett 2017; 1:184-198. [PMID: 30283648 PMCID: PMC6124600 DOI: 10.1002/evl3.20] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 06/01/2017] [Accepted: 07/11/2017] [Indexed: 12/21/2022] Open
Abstract
Deepwater environments are characterized by low levels of available light at narrow spectra, great hydrostatic pressure, and low levels of dissolved oxygen—conditions predicted to exert highly specific selection pressures. In Lake Malawi over 800 cichlid species have evolved, and this adaptive radiation extends into the “twilight zone” below 50 m. We use population‐level RAD‐seq data to investigate whether four endemic deepwater species (Diplotaxodon spp.) have experienced divergent selection within this environment. We identify candidate genes including regulators of photoreceptor function, photopigments, lens morphology, and haemoglobin, many not previously implicated in cichlid adaptive radiations. Colocalization of functionally linked genes suggests coadapted “supergene” complexes. Comparisons of Diplotaxodon to the broader Lake Malawi radiation using genome resequencing data revealed functional substitutions and signatures of positive selection in candidate genes. Our data provide unique insights into genomic adaptation within deepwater habitats, and suggest genome‐level specialization for life at depth as an important process in cichlid radiation.
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Affiliation(s)
- Christoph Hahn
- Evolutionary and Environmental Genomics Group (@EvoHull), School of Environmental Sciences University of Hull Hull HU5 7RX United Kingdom.,Institute of Zoology University of Graz A-8010 Graz Austria
| | - Martin J Genner
- School of Biological Sciences University of Bristol Bristol Life Sciences Building, 24 Tyndall Avenue Bristol BS8 1TQ United Kingdom
| | - George F Turner
- School of Biological Sciences Bangor University Bangor Gwynedd LL57 2UW Wales United Kingdom
| | - Domino A Joyce
- Evolutionary and Environmental Genomics Group (@EvoHull), School of Environmental Sciences University of Hull Hull HU5 7RX United Kingdom
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39
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Selz OM, Thommen R, Pierotti MER, Anaya-Rojas JM, Seehausen O. Differences in male coloration are predicted by divergent sexual selection between populations of a cichlid fish. Proc Biol Sci 2017; 283:rspb.2016.0172. [PMID: 27147097 DOI: 10.1098/rspb.2016.0172] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/11/2016] [Indexed: 12/27/2022] Open
Abstract
Female mating preferences can influence both intraspecific sexual selection and interspecific reproductive isolation, and have therefore been proposed to play a central role in speciation. Here, we investigate experimentally in the African cichlid fish Pundamilia nyererei if differences in male coloration between three para-allopatric populations (i.e. island populations with gene flow) of P. nyererei are predicted by differences in sexual selection by female mate choice between populations. Second, we investigate if female mating preferences are based on the same components of male coloration and go in the same direction when females choose among males of their own population, their own and other conspecific populations and a closely related para-allopatric sister-species, P. igneopinnis Mate-choice experiments revealed that females of the three populations mated species-assortatively, that populations varied in their extent of population-assortative mating and that females chose among males of their own population based on different male colours. Females of different populations exerted directional intrapopulation sexual selection on different male colours, and these differences corresponded in two of the populations to the observed differences in male coloration between the populations. Our results suggest that differences in male coloration between populations of P. nyererei can be explained by divergent sexual selection and that population-assortative mating may directly result from intrapopulation sexual selection.
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Affiliation(s)
- O M Selz
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center for Ecology, Evolution and Biogeochemistry, Seestrasse 79, 6047 Kastanienbaum, Switzerland Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
| | - R Thommen
- Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
| | - M E R Pierotti
- Naos Laboratories, Smithsonian Tropical Research Institute, Panama, Calzada de Amador, Bd 356, 0843-03092, Panama
| | - J M Anaya-Rojas
- Department of Aquatic Ecology, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center for Ecology, Evolution and Biogeochemistry, Seestrasse 79, 6047 Kastanienbaum, Switzerland Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
| | - O Seehausen
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Center for Ecology, Evolution and Biogeochemistry, Seestrasse 79, 6047 Kastanienbaum, Switzerland Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
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40
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Abstract
Extended phenotypes offer a unique opportunity to experimentally manipulate and identify sources of selection acting on traits under natural conditions. The social cichlid fish Neolamprologus multifasciatus builds nests by digging up aquatic snail shells, creating an extended sexual phenotype that is highly amenable to experimental manipulation through addition of extra shells. Here, we find sources of both positive sexual selection and opposing natural selection acting on this trait; augmenting shell nests increases access to mates, but also increases social aggression and predation risk. Increasing the attractiveness of one male also changed social interactions throughout the social network and altered the entire community structure. Manipulated males produced and received more displays from neighbouring females, who also joined augmented male territories at higher rates than unmanipulated groups. However, males in more attractive territories received more aggression from neighbouring males, potentially as a form of social policing. We also detected a significant ecological cost of the ‘over-extended' phenotype; heterospecific predators usurped augmented nests at higher rates, using them as breeding sites and displacing residents. Using these natural experiments, we find that both social and ecological interactions generate clear sources of selection mediating the expression of an extended phenotype in the wild.
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Affiliation(s)
- Lyndon Alexander Jordan
- Department of Collective Behaviour Max Planck Institute for Ornithology, University of Konstanz, Konstanz, Germany Laboratory of Animal Sociology, Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Japan Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Sean M Maguire
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Hans A Hofmann
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA Institute for Cellular and Molecular Biology, Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Masanori Kohda
- Laboratory of Animal Sociology, Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Japan
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41
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Parsons KJ, Concannon M, Navon D, Wang J, Ea I, Groveas K, Campbell C, Albertson RC. Foraging environment determines the genetic architecture and evolutionary potential of trophic morphology in cichlid fishes. Mol Ecol 2016; 25:6012-6023. [PMID: 27516345 DOI: 10.1111/mec.13801] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/13/2016] [Accepted: 07/21/2016] [Indexed: 12/22/2022]
Abstract
Phenotypic plasticity allows organisms to change their phenotype in response to shifts in the environment. While a central topic in current discussions of evolutionary potential, a comprehensive understanding of the genetic underpinnings of plasticity is lacking in systems undergoing adaptive diversification. Here, we investigate the genetic basis of phenotypic plasticity in a textbook adaptive radiation, Lake Malawi cichlid fishes. Specifically, we crossed two divergent species to generate an F3 hybrid mapping population. At early juvenile stages, hybrid families were split and reared in alternate foraging environments that mimicked benthic/scraping or limnetic/sucking modes of feeding. These alternate treatments produced a variation in morphology that was broadly similar to the major axis of divergence among Malawi cichlids, providing support for the flexible stem theory of adaptive radiation. Next, we found that the genetic architecture of several morphological traits was highly sensitive to the environment. In particular, of 22 significant quantitative trait loci (QTL), only one was shared between the environments. In addition, we identified QTL acting across environments with alternate alleles being differentially sensitive to the environment. Thus, our data suggest that while plasticity is largely determined by loci specific to a given environment, it may also be influenced by loci operating across environments. Finally, our mapping data provide evidence for the evolution of plasticity via genetic assimilation at an important regulatory locus, ptch1. In all, our data address long-standing discussions about the genetic basis and evolution of plasticity. They also underscore the importance of the environment in affecting developmental outcomes, genetic architectures, morphological diversity and evolutionary potential.
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Affiliation(s)
- Kevin J Parsons
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Moira Concannon
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Dina Navon
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jason Wang
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Ilene Ea
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Kiran Groveas
- Fundamentals of Science Research Program, Ossining High School, Ossining, NY, 10562, USA
| | - Calum Campbell
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - R Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
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42
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Butler JM, Maruska KP. The Mechanosensory Lateral Line System Mediates Activation of Socially-Relevant Brain Regions during Territorial Interactions. Front Behav Neurosci 2016; 10:93. [PMID: 27242462 PMCID: PMC4865491 DOI: 10.3389/fnbeh.2016.00093] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/29/2016] [Indexed: 11/13/2022] Open
Abstract
Animals use multiple senses during social interactions and must integrate this information in the brain to make context-dependent behavioral decisions. For fishes, the largest group of vertebrates, the mechanosensory lateral line system provides crucial hydrodynamic information for survival behaviors, but little is known about its function in social communication. Our previous work using the African cichlid fish, Astatotilapia burtoni, provided the first empirical evidence that fish use their lateral line system to detect water movements from conspecifics for mutual assessment and behavioral choices. It is unknown, however, where this socially-relevant mechanosensory information is processed in the brain to elicit adaptive behavioral responses. To examine for the first time in any fish species which brain regions receive contextual mechanosensory information, we quantified expression of the immediate early gene cfos as a proxy for neural activation in sensory and socially-relevant brain nuclei from lateral line-intact and -ablated fish following territorial interactions. Our in situ hybridization results indicate that in addition to known lateral line processing regions, socially-relevant mechanosensory information is processed in the ATn (ventromedial hypothalamus homolog), Dl (putative hippocampus homolog), and Vs (putative medial extended amygdala homolog). In addition, we identified a functional network within the conserved social decision-making network (SDMN) whose co-activity corresponds with mutual assessment and behavioral choice. Lateral line-intact and –ablated fight winners had different patterns of co-activity of these function networks and group identity could be determined solely by activation patterns, indicating the importance of mechanoreception to co-activity of the SDMN. These data show for the first time that the mechanosensory lateral line system provides relevant information to conserved decision-making centers of the brain during territorial interactions to mediate crucial behavioral choices such as whether or not to engage in a territorial fight. To our knowledge, this is also the first evidence of a subpallial nucleus receiving mechanosensory input, providing important information for elucidating homologies of decision-making circuits across vertebrates. These novel results highlight the importance of considering multimodal sensory input in mediating context-appropriate behaviors that will provide broad insights on the evolution of decision-making networks across all taxa.
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Affiliation(s)
- Julie M Butler
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
| | - Karen P Maruska
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
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43
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Ogawa S, Sivalingam M, Biran J, Golan M, Anthonysamy RS, Levavi-Sivan B, Parhar IS. Distribution of LPXRFa, a gonadotropin-inhibitory hormone ortholog peptide, and LPXRFa receptor in the brain and pituitary of the tilapia. J Comp Neurol 2016; 524:2753-75. [PMID: 26917324 DOI: 10.1002/cne.23990] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 11/09/2022]
Abstract
In vertebrates, gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH), respectively, regulate reproduction in positive and negative manners. GnIH belongs to the LPXRFa family of peptides previously identified in mammalian and nonmammalian vertebrates. Studying the detailed distribution of LPXRFa as well as its receptor (LPXRFa-R) in the brain and pituitary is important for understanding their multiple action sites and potential functions. However, the distribution of LPXRFa and LPXRFa-R has not been studied in teleost species, partially because of the lack of fish-specific antibodies. Therefore, in the present study, we generated specific antibodies against LPXRFa and its receptor from Nile tilapia (Oreochromis niloticus), and examined their distributions in the brain and pituitary by immunohistochemistry. Tilapia LPXRFa-immunoreactive neurons lie in the posterior ventricular nucleus of the caudal preoptic area, whereas LPXRFa-R-immunoreactive cells are distributed widely. Double immunofluorescence showed that neither LPXRFa-immunoreactive fibers nor LPXRFa-R is closely associated or coexpressed with GnRH1, GnRH3, or kisspeptin (Kiss2) neurons. In the pituitary, LPXRFa fibers are closely associated with gonadotropic endocrine cells [expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], with adrenocorticomelanotropic cells [corticotropin (ACTH) and α-melanotropin (α-MSH)], and with somatolactin endocrine cells. In contrast, LPXRFa-R are expressed only in LH, ACTH, and α-MSH cells. These results suggest that LPXRFa and LPXRFa-R signaling acts directly on the pituitary cells independent from GnRH or kisspeptin and could play multiple roles in reproductive and nonreproductive functions in teleosts. J. Comp. Neurol. 524:2753-2775, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Mageswary Sivalingam
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Jakob Biran
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Matan Golan
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Rachel Shalini Anthonysamy
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
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44
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Abstract
Gene regulatory networks (GRN) are central to developmental processes. They are composed of transcription factors and signaling molecules orchestrating gene expression modules that tightly regulate the development of organisms. The neural crest (NC) is a multipotent cell population that is considered a key innovation of vertebrates. Its derivatives contribute to shaping the astounding morphological diversity of jaws, teeth, head skeleton, or pigmentation. Here, we study the molecular evolution of the NC GRN by analyzing patterns of molecular divergence for a total of 36 genes in 16 species of bony fishes. Analyses of nonsynonymous to synonymous substitution rate ratios (dN/dS) support patterns of variable selective pressures among genes deployed at different stages of NC development, consistent with the developmental hourglass model. Model-based clustering techniques of sequence features support the notion of extreme conservation of NC-genes across the entire network. Our data show that most genes are under strong purifying selection that is maintained throughout ray-finned fish evolution. Late NC development genes reveal a pattern of increased constraints in more recent lineages. Additionally, seven of the NC-genes showed signs of relaxation of purifying selection in the famously species-rich lineage of cichlid fishes. This suggests that NC genes might have played a role in the adaptive radiation of cichlids by granting flexibility in the development of NC-derived traits-suggesting an important role for NC network architecture during the diversification in vertebrates.
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Affiliation(s)
- Claudius F Kratochwil
- Department of Biology, University of Konstanz, Germany Zukunftskolleg, University of Konstanz, Germany
| | | | - Iker Irisarri
- Department of Biology, University of Konstanz, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, Germany
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45
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Grone BP, Maruska KP. Divergent evolution of two corticotropin-releasing hormone (CRH) genes in teleost fishes. Front Neurosci 2015; 9:365. [PMID: 26528116 PMCID: PMC4602089 DOI: 10.3389/fnins.2015.00365] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/22/2015] [Indexed: 11/13/2022] Open
Abstract
Genome duplication, thought to have happened twice early in vertebrate evolution and a third time in teleost fishes, gives rise to gene paralogs that can evolve subfunctions or neofunctions via sequence and regulatory changes. To explore the evolution and functions of corticotropin-releasing hormone (CRH), we searched sequenced teleost genomes for CRH paralogs. Our phylogenetic and synteny analyses indicate that two CRH genes, crha and crhb, evolved via duplication of crh1 early in the teleost lineage. We examined the expression of crha and crhb in two teleost species from different orders: an African cichlid, Burton's mouthbrooder, (Astatotilapia burtoni; Order Perciformes) and zebrafish (Danio rerio; Order Cypriniformes). Furthermore, we compared expression of the teleost crha and crhb genes with the crh1 gene of an outgroup to the teleost clade: the spotted gar (Lepisosteus oculatus). In situ hybridization for crha and crhb mRNA in brains and eyes revealed distinct expression patterns for crha in different teleost species. In the cichlid, crha mRNA was found in the retina but not in the brain. In zebrafish, however, crha mRNA was not found in the retina, but was detected in the brain, restricted to the ventral hypothalamus. Spotted gar crh1 was found in the retina as well as the brain, suggesting that the ancestor of teleost fishes likely had a crh1 gene expressed in both retina and brain. Thus, genome duplication may have freed crha from constraints, allowing it to evolve distinct sequences, expression patterns, and likely unique functions in different lineages.
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Affiliation(s)
- Brian P Grone
- Department of Neurological Surgery, University of California, San Francisco San Francisco, CA, USA
| | - Karen P Maruska
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
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46
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Dalton BE, Lu J, Leips J, Cronin TW, Carleton KL. Variable light environments induce plastic spectral tuning by regional opsin coexpression in the African cichlid fish, Metriaclima zebra. Mol Ecol 2015; 24:4193-204. [PMID: 26175094 PMCID: PMC4532641 DOI: 10.1111/mec.13312] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/02/2015] [Accepted: 07/07/2015] [Indexed: 01/29/2023]
Abstract
Critical behaviours such as predation and mate choice often depend on vision. Visual systems are sensitive to the spectrum of light in their environment, which can vary extensively both within and among habitats. Evolutionary changes in spectral sensitivity contribute to divergence and speciation. Spectral sensitivity of the retina is primarily determined by visual pigments, which are opsin proteins bound to a chromophore. We recently discovered that photoreceptors in different regions of the retina, which view objects against distinct environmental backgrounds, coexpress different pairs of opsins in an African cichlid fish, Metriaclima zebra. This coexpression tunes the sensitivity of the retinal regions to the corresponding backgrounds and may aid in detection of dark objects, such as predators. Although intraretinal regionalization of spectral sensitivity in many animals correlates with their light environments, it is unknown whether variation in the light environment induces developmentally plastic alterations of intraretinal sensitivity regions. Here, we demonstrate with fluorescent in situ hybridization and qPCR that the spectrum and angle of environmental light both influence the development of spectral sensitivity regions by altering the distribution and level of opsins across the retina. Normally, M. zebra coexpresses LWS opsin with RH2Aα opsin in double cones of the ventral but not the dorsal retina. However, when illuminated from below throughout development, adult M. zebra coexpressed LWS and RH2Aα in double cones both dorsally and ventrally. Thus, environmental background spectra alter the spectral sensitivity pattern that develops across the retina, potentially influencing behaviours and related evolutionary processes such as courtship and speciation.
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Affiliation(s)
- Brian E Dalton
- Department of Biology, University of Maryland, Baltimore County, MD, 21250, USA
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
| | - Jessica Lu
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
| | - Jeff Leips
- Department of Biology, University of Maryland, Baltimore County, MD, 21250, USA
| | - Thomas W Cronin
- Department of Biology, University of Maryland, Baltimore County, MD, 21250, USA
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
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Dalton BE, Loew ER, Cronin TW, Carleton KL. Spectral tuning by opsin coexpression in retinal regions that view different parts of the visual field. Proc Biol Sci 2015; 281:rspb.2014.1980. [PMID: 25377457 DOI: 10.1098/rspb.2014.1980] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Vision frequently mediates critical behaviours, and photoreceptors must respond to the light available to accomplish these tasks. Most photoreceptors are thought to contain a single visual pigment, an opsin protein bound to a chromophore, which together determine spectral sensitivity. Mechanisms of spectral tuning include altering the opsin, changing the chromophore and incorporating pre-receptor filtering. A few exceptions to the use of a single visual pigment have been documented in which a single mature photoreceptor coexpresses opsins that form spectrally distinct visual pigments, and in these exceptions the functional significance of coexpression is unclear. Here we document for the first time photoreceptors coexpressing spectrally distinct opsin genes in a manner that tunes sensitivity to the light environment. Photoreceptors of the cichlid fish, Metriaclima zebra, mix different pairs of opsins in retinal regions that view distinct backgrounds. The mixing of visual pigments increases absorbance of the corresponding background, potentially aiding the detection of dark objects. Thus, opsin coexpression may be a novel mechanism of spectral tuning that could be useful for detecting prey, predators and mates. However, our calculations show that coexpression of some opsins can hinder colour discrimination, creating a trade-off between visual functions.
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Affiliation(s)
- Brian E Dalton
- Department of Biology, University of Maryland, Baltimore County, MD 21250, USA Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Ellis R Loew
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Thomas W Cronin
- Department of Biology, University of Maryland, Baltimore County, MD 21250, USA
| | - Karen L Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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Ford AGP, Dasmahapatra KK, Rüber L, Gharbi K, Cezard T, Day JJ. High levels of interspecific gene flow in an endemic cichlid fish adaptive radiation from an extreme lake environment. Mol Ecol 2015; 24:3421-40. [PMID: 25997156 PMCID: PMC4973668 DOI: 10.1111/mec.13247] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/13/2015] [Accepted: 05/13/2015] [Indexed: 12/30/2022]
Abstract
Studying recent adaptive radiations in isolated insular systems avoids complicating causal events and thus may offer clearer insight into mechanisms generating biological diversity. Here, we investigate evolutionary relationships and genomic differentiation within the recent radiation of Alcolapia cichlid fish that exhibit extensive phenotypic diversification, and which are confined to the extreme soda lakes Magadi and Natron in East Africa. We generated an extensive RAD data set of 96 individuals from multiple sampling sites and found evidence for genetic admixture between species within Lake Natron, with the highest levels of admixture between sympatric populations of the most recently diverged species. Despite considerable environmental separation, populations within Lake Natron do not exhibit isolation by distance, indicating panmixia within the lake, although individuals within lineages clustered by population in phylogenomic analysis. Our results indicate exceptionally low genetic differentiation across the radiation despite considerable phenotypic trophic variation, supporting previous findings from smaller data sets; however, with the increased power of densely sampled SNPs, we identify genomic peaks of differentiation (FST outliers) between Alcolapia species. While evidence of ongoing gene flow and interspecies hybridization in certain populations suggests that Alcolapia species are incompletely reproductively isolated, the identification of outlier SNPs under diversifying selection indicates the radiation is undergoing adaptive divergence.
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Affiliation(s)
- Antonia G P Ford
- Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
| | | | - Lukas Rüber
- Naturhistorisches Museum der Burgergemeinde Bern, Bernastrasse 15, Bern, 3005, Switzerland
| | - Karim Gharbi
- Edinburgh Genomics, Ashworth Laboratories, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Timothee Cezard
- Edinburgh Genomics, Ashworth Laboratories, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Julia J Day
- Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
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Ma Y, Juntti SA, Hu CK, Huguenard JR, Fernald RD. Electrical synapses connect a network of gonadotropin releasing hormone neurons in a cichlid fish. Proc Natl Acad Sci U S A 2015; 112:3805-10. [PMID: 25775522 DOI: 10.1073/pnas.1421851112] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Initiating and regulating vertebrate reproduction requires pulsatile release of gonadotropin-releasing hormone (GnRH1) from the hypothalamus. Coordinated GnRH1 release, not simply elevated absolute levels, effects the release of pituitary gonadotropins that drive steroid production in the gonads. However, the mechanisms underlying synchronization of GnRH1 neurons are unknown. Control of synchronicity by gap junctions between GnRH1 neurons has been proposed but not previously found. We recorded simultaneously from pairs of transgenically labeled GnRH1 neurons in adult male Astatotilapia burtoni cichlid fish. We report that GnRH1 neurons are strongly and uniformly interconnected by electrical synapses that can drive spiking in connected cells and can be reversibly blocked by meclofenamic acid. Our results suggest that electrical synapses could promote coordinated spike firing in a cellular assemblage of GnRH1 neurons to produce the pulsatile output necessary for activation of the pituitary and reproduction.
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Schaedelin FC, van Dongen WFD, Wagner RH. Mate choice and genetic monogamy in a biparental, colonial fish. Behav Ecol 2015; 26:782-788. [PMID: 26023276 PMCID: PMC4433329 DOI: 10.1093/beheco/arv011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 01/05/2015] [Accepted: 01/17/2015] [Indexed: 11/22/2022] Open
Abstract
We report a rare case of genetic monogamy in a biparental fish species. Males and females paired assortatively by size, which is compatible with mutual mate choice. Mate choice in monogamous species is interesting because both sexes provide essential parental care, making males, as well as females, choosy. Social monogamy in the form of biparental care is well known from a variety of species, but uncommon in fish. In socially monogamous species, in which both sexes provide essential parental care, males as well as females are expected to be choosy. Whereas hundreds of studies have examined monogamy in biparental birds, only several such studies exist in fish. We examined mate choice in the biparental, colonial cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika, Zambia. We genotyped more than 350 individuals at 11 microsatellite loci to investigate their mating system. We found no extrapair paternity, identifying this biparental fish as genetically monogamous. Breeders paired randomly according to their genetic similarity, suggesting a lack of selection against inbreeding avoidance. We further found that breeders paired assortatively by body size, a criterion of quality in fish, suggesting mutual mate choice. In a subsequent mate preference test in an aquarium setup, females showed a strong preference for male size by laying eggs near the larger of 2 males in 13 of 14 trials.
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Affiliation(s)
- Franziska C Schaedelin
- Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna , Savoyenstrasse 1a, 1160 Vienna , Austria
| | - Wouter F D van Dongen
- Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna , Savoyenstrasse 1a, 1160 Vienna , Austria
| | - Richard H Wagner
- Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine Vienna , Savoyenstrasse 1a, 1160 Vienna , Austria
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