1
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Cobham AE, Rohner N. Unraveling stress resilience: Insights from adaptations to extreme environments by Astyanax mexicanus cavefish. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:178-188. [PMID: 38247307 DOI: 10.1002/jez.b.23238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 12/26/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
Extreme environmental conditions have profound impacts on shaping the evolutionary trajectory of organisms. Exposure to these conditions elicits stress responses, that can trigger phenotypic changes in novel directions. The Mexican Tetra, Astyanax mexicanus, is an excellent model for understanding evolutionary mechanisms in response to extreme or new environments. This fish species consists of two morphs; the classical surface-dwelling fish and the blind cave-dwellers that inhabit dark and biodiversity-reduced ecosystems. In this review, we explore the specific stressors present in cave environments and examine the diverse adaptive strategies employed by cave populations to not only survive but thrive as successful colonizers. By analyzing the evolutionary responses of A. mexicanus, we gain valuable insights into the genetic, physiological, and behavioral adaptations that enable organisms to flourish under challenging environmental conditions.
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Affiliation(s)
- Ansa E Cobham
- Stowers Institute for Medical Research, Missouri, Kansas City, USA
| | - Nicolas Rohner
- Stowers Institute for Medical Research, Missouri, Kansas City, USA
- Department of Cell Biology & Physiology, University of Kansas Medical Center, Kansas City, Missouri, USA
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2
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Rodríguez-Morales R. Sensing in the dark: Constructive evolution of the lateral line system in blind populations of Astyanax mexicanus. Ecol Evol 2024; 14:e11286. [PMID: 38654714 PMCID: PMC11036076 DOI: 10.1002/ece3.11286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/26/2024] [Accepted: 04/03/2024] [Indexed: 04/26/2024] Open
Abstract
Cave-adapted animals evolve a suite of regressive and constructive traits that allow survival in the dark. Most studies aiming at understanding cave animal evolution have focused on the genetics and environmental underpinnings of regressive traits, with special emphasis on vision loss. Possibly as a result of vision loss, other non-visual sensory systems have expanded and compensated in cave species. For instance, in many cave-dwelling fish species, including the blind cavefish of the Mexican tetra, Astyanax mexicanus, a major non-visual mechanosensory system called the lateral line, compensated for vision loss through morphological expansions. While substantial work has shed light on constructive adaptation of this system, there are still many open questions regarding its developmental origin, synaptic plasticity, and overall adaptive value. This review provides a snapshot of the current state of knowledge of lateral line adaption in A. mexicanus, with an emphasis on anatomy, synaptic plasticity, and behavior. Multiple open avenues for future research in this system, and how these can be leveraged as tools for both evolutionary biology and evolutionary medicine, are discussed.
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Affiliation(s)
- Roberto Rodríguez-Morales
- Department of Anatomy & Neurobiology, School of Medicine University of Puerto Rico San Juan Puerto Rico
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3
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Ponnimbaduge Perera P, Perez Guerra D, Riddle MR. The Mexican Tetra, Astyanax mexicanus, as a Model System in Cell and Developmental Biology. Annu Rev Cell Dev Biol 2023; 39:23-44. [PMID: 37437210 DOI: 10.1146/annurev-cellbio-012023-014003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Our understanding of cell and developmental biology has been greatly aided by a focus on a small number of model organisms. However, we are now in an era where techniques to investigate gene function can be applied across phyla, allowing scientists to explore the diversity and flexibility of developmental mechanisms and gain a deeper understanding of life. Researchers comparing the eyeless cave-adapted Mexican tetra, Astyanax mexicanus, with its river-dwelling counterpart are revealing how the development of the eyes, pigment, brain, cranium, blood, and digestive system evolves as animals adapt to new environments. Breakthroughs in our understanding of the genetic and developmental basis of regressive and constructive trait evolution have come from A. mexicanus research. They include understanding the types of mutations that alter traits, which cellular and developmental processes they affect, and how they lead to pleiotropy. We review recent progress in the field and highlight areas for future investigations that include evolution of sex differentiation, neural crest development, and metabolic regulation of embryogenesis.
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Affiliation(s)
| | | | - Misty R Riddle
- Department of Biology, University of Nevada, Reno, Nevada, USA;
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4
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Corral-Lopez A, Kotrschal A, Szorkovszky A, Garate-Olaizola M, Herbert-Read J, van der Bijl W, Romenskyy M, Zeng HL, Buechel SD, Fontrodona-Eslava A, Pelckmans K, Mank JE, Kolm N. Evolution of schooling drives changes in neuroanatomy and motion characteristics across predation contexts in guppies. Nat Commun 2023; 14:6027. [PMID: 37758730 PMCID: PMC10533906 DOI: 10.1038/s41467-023-41635-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
One of the most spectacular displays of social behavior is the synchronized movements that many animal groups perform to travel, forage and escape from predators. However, elucidating the neural mechanisms underlying the evolution of collective behaviors, as well as their fitness effects, remains challenging. Here, we study collective motion patterns with and without predation threat and predator inspection behavior in guppies experimentally selected for divergence in polarization, an important ecological driver of coordinated movement in fish. We find that groups from artificially selected lines remain more polarized than control groups in the presence of a threat. Neuroanatomical measurements of polarization-selected individuals indicate changes in brain regions previously suggested to be important regulators of perception, fear and attention, and motor response. Additional visual acuity and temporal resolution tests performed in polarization-selected and control individuals indicate that observed differences in predator inspection and schooling behavior should not be attributable to changes in visual perception, but rather are more likely the result of the more efficient relay of sensory input in the brain of polarization-selected fish. Our findings highlight that brain morphology may play a fundamental role in the evolution of coordinated movement and anti-predator behavior.
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Affiliation(s)
- Alberto Corral-Lopez
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada.
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden.
- Division of Biosciences, University College London, London, UK.
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
| | - Alexander Kotrschal
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
- Behavioural Ecology, Wageningen University & Research, Wageningen, Netherlands
| | - Alexander Szorkovszky
- RITMO Centre for Interdisciplinary Studies in Rhythm, Time and Motion, University of Oslo, Oslo, Norway
| | - Maddi Garate-Olaizola
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - James Herbert-Read
- Department of Zoology, University of Cambridge, Cambridge, UK
- Aquatic Ecology, Lund University, Lund, Sweden
| | - Wouter van der Bijl
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - Maksym Romenskyy
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
- Department of Life Sciences, Imperial College London, London, UK
| | - Hong-Li Zeng
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing, China
| | - Severine Denise Buechel
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
- Behavioural Ecology, Wageningen University & Research, Wageningen, Netherlands
| | - Ada Fontrodona-Eslava
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, UK
| | | | - Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - Niclas Kolm
- Department of Zoology/Ethology, Stockholm University, Stockholm, Sweden
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5
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Paz A, Holt KJ, Clarke A, Aviles A, Abraham B, Keene AC, Duboué ER, Fily Y, Kowalko JE. Changes in local interaction rules during ontogeny underlie the evolution of collective behavior. iScience 2023; 26:107431. [PMID: 37636065 PMCID: PMC10448030 DOI: 10.1016/j.isci.2023.107431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/17/2023] [Accepted: 07/17/2023] [Indexed: 08/29/2023] Open
Abstract
Collective motion emerges from individual interactions which produce group-wide patterns in behavior. While adaptive changes to collective motion are observed across animal species, how local interactions change when these collective behaviors evolve is poorly understood. Here, we use the Mexican tetra, Astyanax mexicanus, which exists as a schooling surface form and a non-schooling cave form, to study differences in how fish alter their swimming in response to neighbors across ontogeny and between evolutionarily diverged populations. We find that surface fish undergo a transition to schooling mediated by changes in the way fish modulate speed and turning relative to neighbors. This transition begins with the tendency to align to neighbors emerging by 28 days post-fertilization and ends with the emergence of robust attraction by 70 days post-fertilization. Cavefish exhibit neither alignment nor attraction at any stage of development. These results reveal how evolution alters local interactions to produce striking differences in collective behavior.
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Affiliation(s)
- Alexandra Paz
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Karla J. Holt
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Anik Clarke
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Ari Aviles
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Briana Abraham
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Alex C. Keene
- Department of Biology, Texas A&M, College Station, TX 77840, USA
| | - Erik R. Duboué
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Johanna E. Kowalko
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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6
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Sifuentes-Romero I, Aviles AM, Carter JL, Chan-Pong A, Clarke A, Crotty P, Engstrom D, Meka P, Perez A, Perez R, Phelan C, Sharrard T, Smirnova MI, Wade AJ, Kowalko JE. Trait Loss in Evolution: What Cavefish Have Taught Us about Mechanisms Underlying Eye Regression. Integr Comp Biol 2023; 63:393-406. [PMID: 37218721 PMCID: PMC10445413 DOI: 10.1093/icb/icad032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Reduction or complete loss of traits is a common occurrence throughout evolutionary history. In spite of this, numerous questions remain about why and how trait loss has occurred. Cave animals are an excellent system in which these questions can be answered, as multiple traits, including eyes and pigmentation, have been repeatedly reduced or lost across populations of cave species. This review focuses on how the blind Mexican cavefish, Astyanax mexicanus, has been used as a model system for examining the developmental, genetic, and evolutionary mechanisms that underlie eye regression in cave animals. We focus on multiple aspects of how eye regression evolved in A. mexicanus, including the developmental and genetic pathways that contribute to eye regression, the effects of the evolution of eye regression on other traits that have also evolved in A. mexicanus, and the evolutionary forces contributing to eye regression. We also discuss what is known about the repeated evolution of eye regression, both across populations of A. mexicanus cavefish and across cave animals more generally. Finally, we offer perspectives on how cavefish can be used in the future to further elucidate mechanisms underlying trait loss using tools and resources that have recently become available.
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Affiliation(s)
- Itzel Sifuentes-Romero
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Ari M Aviles
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
- Department of Cell Biology and Genetics, Texas A&M University, College Station, TX 77843, USA
| | - Joseph L Carter
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Allen Chan-Pong
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Anik Clarke
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Patrick Crotty
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - David Engstrom
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Pranav Meka
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Alexandra Perez
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Riley Perez
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Christine Phelan
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Taylor Sharrard
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Maria I Smirnova
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA
- Stiles–Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, USA
- Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Amanda J Wade
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
| | - Johanna E Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter FL 33458, USA
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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7
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Kozol RA, Conith AJ, Yuiska A, Cree-Newman A, Tolentino B, Benesh K, Paz A, Lloyd E, Kowalko JE, Keene AC, Albertson C, Duboue ER. A brain-wide analysis maps structural evolution to distinct anatomical module. eLife 2023; 12:e80777. [PMID: 37498318 PMCID: PMC10435234 DOI: 10.7554/elife.80777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/26/2023] [Indexed: 07/28/2023] Open
Abstract
The vertebrate brain is highly conserved topologically, but less is known about neuroanatomical variation between individual brain regions. Neuroanatomical variation at the regional level is hypothesized to provide functional expansion, building upon ancestral anatomy needed for basic functions. Classically, animal models used to study evolution have lacked tools for detailed anatomical analysis that are widely used in zebrafish and mice, presenting a barrier to studying brain evolution at fine scales. In this study, we sought to investigate the evolution of brain anatomy using a single species of fish consisting of divergent surface and cave morphs, that permits functional genetic testing of regional volume and shape across the entire brain. We generated a high-resolution brain atlas for the blind Mexican cavefish Astyanax mexicanus and coupled the atlas with automated computational tools to directly assess variability in brain region shape and volume across all populations. We measured the volume and shape of every grossly defined neuroanatomical region of the brain and assessed correlations between anatomical regions in surface fish, cavefish, and surface × cave F2 hybrids, whose phenotypes span the range of surface to cave. We find that dorsal regions of the brain are contracted, while ventral regions have expanded, with F2 hybrid data providing support for developmental constraint along the dorsal-ventral axis. Furthermore, these dorsal-ventral relationships in anatomical variation show similar patterns for both volume and shape, suggesting that the anatomical evolution captured by these two parameters could be driven by similar developmental mechanisms. Together, these data demonstrate that A. mexicanus is a powerful system for functionally determining basic principles of brain evolution and will permit testing how genes influence early patterning events to drive brain-wide anatomical evolution.
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Affiliation(s)
- Robert A Kozol
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Andrew J Conith
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
| | - Anders Yuiska
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Alexia Cree-Newman
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Bernadeth Tolentino
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Kasey Benesh
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Alexandra Paz
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
| | - Evan Lloyd
- Department of Biology, Texas A&M UniversityCollege StationUnited States
| | - Johanna E Kowalko
- Department of Biological Sciences, Lehigh UniversityBethlehemUnited States
| | - Alex C Keene
- Department of Biology, Texas A&M UniversityCollege StationUnited States
| | - Craig Albertson
- Department of Biology, University of Massachusetts AmherstAmherstUnited States
| | - Erik R Duboue
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
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8
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Rohner N. The cavefish Astyanax mexicanus. Nat Methods 2023; 20:948-950. [PMID: 37434002 DOI: 10.1038/s41592-023-01916-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Affiliation(s)
- Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, MO, USA.
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9
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Paz A, Holt KJ, Clarke A, Aviles A, Abraham B, Keene AC, Duboué ER, Fily Y, Kowalko JE. Changes in local interaction rules during ontogeny underlie the evolution of collective behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534467. [PMID: 37034671 PMCID: PMC10081253 DOI: 10.1101/2023.03.28.534467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Collective motion emerges from individual interactions which produce groupwide patterns in behavior. While adaptive changes to collective motion are observed across animal species, how local interactions change when these collective behaviors evolve is poorly understood. Here, we use the Mexican tetra, A. mexicanus, which exists as a schooling surface form and a non-schooling cave form, to study differences in how fish alter their swimming in response to neighbors across ontogeny and between evolutionarily diverged populations. We find that surface fish undergo a transition to schooling during development that occurs through increases in inter-individual alignment and attraction mediated by changes in the way fish modulate speed and turning relative to neighbors. Cavefish, which have evolved loss of schooling, exhibit neither of these schooling-promoting interactions at any stage of development. These results reveal how evolution alters local interaction rules to produce striking differences in collective behavior.
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Affiliation(s)
- Alexandra Paz
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Karla J. Holt
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Anik Clarke
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Ari Aviles
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Briana Abraham
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | | | - Erik R. Duboué
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
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10
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Conith AJ, Hope SA, Albertson RC. Covariation of brain and skull shapes as a model to understand the role of crosstalk in development and evolution. Evol Dev 2023; 25:85-102. [PMID: 36377237 PMCID: PMC9839637 DOI: 10.1111/ede.12421] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/24/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022]
Abstract
Covariation among discrete phenotypes can arise due to selection for shared functions, and/or shared genetic and developmental underpinnings. The consequences of such phenotypic integration are far-reaching and can act to either facilitate or limit morphological variation. The vertebrate brain is known to act as an "organizer" of craniofacial development, secreting morphogens that can affect the shape of the growing neurocranium, consistent with roles for pleiotropy in brain-neurocranium covariation. Here, we test this hypothesis in cichlid fishes by first examining the degree of shape integration between the brain and the neurocranium using three-dimensional geometric morphometrics in an F5 hybrid population, and then genetically mapping trait covariation using quantitative trait loci (QTL) analysis. We observe shape associations between the brain and the neurocranium, a pattern that holds even when we assess associations between the brain and constituent parts of the neurocranium: the rostrum and braincase. We also recover robust genetic signals for both hard- and soft-tissue traits and identify a genomic region where QTL for the brain and braincase overlap, implicating a role for pleiotropy in patterning trait covariation. Fine mapping of the overlapping genomic region identifies a candidate gene, notch1a, which is known to be involved in patterning skeletal and neural tissues during development. Taken together, these data offer a genetic hypothesis for brain-neurocranium covariation, as well as a potential mechanism by which behavioral shifts may simultaneously drive rapid change in neuroanatomy and craniofacial morphology.
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Affiliation(s)
- Andrew J. Conith
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01002,Corresponding authors: AJC: , RCA:
| | - Sylvie A. Hope
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01002
| | - R. Craig Albertson
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01002,Corresponding authors: AJC: , RCA:
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11
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Kuhn J, Azari S, Volkoff H. Effects of temperature on food intake and the expression of appetite regulators in three Characidae fish: The black-skirted tetra (Gymnocorymbus ternetzi), neon tetra (Paracheirodon innesi) and Mexican cavefish (Astyanax mexicanus). Comp Biochem Physiol A Mol Integr Physiol 2023; 275:111333. [PMID: 36244591 DOI: 10.1016/j.cbpa.2022.111333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/06/2022] [Accepted: 10/09/2022] [Indexed: 11/07/2022]
Abstract
The Characidae family of fish is composed of commercially important species for which little is known about the regulation of feeding. Fish are ectotherms so that their body temperature fluctuates with the temperature of the surrounding water. Changes in water temperature can thus have major effects on the physiology of fish, in particular their feeding. The mechanisms by which appetite is influenced by changes in temperatures in fish remain unclear. In this study, we examined the effects of temperature on feeding behavior, food intake and the expression of appetite regulators in three characid fish (black tetra, neon tetra and cavefish) by submitting them to four different temperatures for 2 weeks (20°C, 24°C, 28°C, 32°C). In all species, food intake increased with increasing temperature. In neon and black tetras, increasing temperatures decreased expressions of orexin and leptin and increased that of cocaine and amphetamine regulated transcript (CART). In cavefish, temperature had no effect on brain orexin, leptin or CART. In all three species, higher temperatures induced increases in intestine expression of cholecystokinin (CCK), but no effects were seen for intestine ghrelin and peptide YY expressions. Our results show that temperature affects feeding in Characidae fish and induces species-specific changes in the expression of appetite regulators.
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Affiliation(s)
- Jannik Kuhn
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada; Hochschule Mannheim University, Mannheim 68163, Germany
| | - Sepideh Azari
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada
| | - Helene Volkoff
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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12
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Suarez LE, Yovel Y, van den Heuvel MP, Sporns O, Assaf Y, Lajoie G, Misic B. A connectomics-based taxonomy of mammals. eLife 2022; 11:e78635. [PMID: 36342363 PMCID: PMC9681214 DOI: 10.7554/elife.78635] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Mammalian taxonomies are conventionally defined by morphological traits and genetics. How species differ in terms of neural circuits and whether inter-species differences in neural circuit organization conform to these taxonomies is unknown. The main obstacle to the comparison of neural architectures has been differences in network reconstruction techniques, yielding species-specific connectomes that are not directly comparable to one another. Here, we comprehensively chart connectome organization across the mammalian phylogenetic spectrum using a common reconstruction protocol. We analyse the mammalian MRI (MaMI) data set, a database that encompasses high-resolution ex vivo structural and diffusion MRI scans of 124 species across 12 taxonomic orders and 5 superorders, collected using a unified MRI protocol. We assess similarity between species connectomes using two methods: similarity of Laplacian eigenspectra and similarity of multiscale topological features. We find greater inter-species similarities among species within the same taxonomic order, suggesting that connectome organization reflects established taxonomic relationships defined by morphology and genetics. While all connectomes retain hallmark global features and relative proportions of connection classes, inter-species variation is driven by local regional connectivity profiles. By encoding connectomes into a common frame of reference, these findings establish a foundation for investigating how neural circuits change over phylogeny, forging a link from genes to circuits to behaviour.
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Affiliation(s)
- Laura E Suarez
- Montréal Neurological Institute, McGill UniversityMontrealCanada
- Mila - Quebec Artificial Intelligence InstituteMontrealCanada
| | - Yossi Yovel
- School of Neurobiology, Biochemistry and Biophysics, Tel Aviv UniversityTel AvivIsrael
| | - Martijn P van den Heuvel
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit AmsterdamAmsterdamNetherlands
| | - Olaf Sporns
- Psychological and Brain Sciences, Indiana UniversityBloomingtonUnited States
| | - Yaniv Assaf
- School of Neurobiology, Biochemistry and Biophysics, Tel Aviv UniversityTel AvivIsrael
| | | | - Bratislav Misic
- Montréal Neurological Institute, McGill UniversityMontrealCanada
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13
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Roberts RJV, Pop S, Prieto-Godino LL. Evolution of central neural circuits: state of the art and perspectives. Nat Rev Neurosci 2022; 23:725-743. [DOI: 10.1038/s41583-022-00644-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2022] [Indexed: 11/09/2022]
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14
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Rodriguez-Morales R, Gonzalez-Lerma P, Yuiska A, Han JH, Guerra Y, Crisostomo L, Keene AC, Duboue ER, Kowalko JE. Convergence on reduced aggression through shared behavioral traits in multiple populations of Astyanax mexicanus. BMC Ecol Evol 2022; 22:116. [PMID: 36241984 PMCID: PMC9563175 DOI: 10.1186/s12862-022-02069-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background Results Conclusion Supplementary information
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Affiliation(s)
- Roberto Rodriguez-Morales
- grid.259029.50000 0004 1936 746XDepartment of Biological Sciences, Lehigh University, 18015 Bethlehem, PA USA
| | - Paola Gonzalez-Lerma
- grid.255951.fDepartment of Integrative Biology and Biomedical Sciences, Florida Atlantic University, 33431 Boca Raton, FL USA
| | - Anders Yuiska
- grid.255951.fCharles E. Schmidt College of Science, Florida Atlantic University, 33431 Boca Raton, FL USA
| | - Ji Heon Han
- grid.255951.fCharles E. Schmidt College of Science, Florida Atlantic University, 33431 Boca Raton, FL USA ,grid.255951.fProgram in Integrative Biology and Neuroscience, Florida Atlantic University, 33458 Jupiter, FL USA
| | - Yolanda Guerra
- grid.255951.fHarriet L. Wilkes Honors College, Florida Atlantic University, 33458 Jupiter, FL USA
| | - Lina Crisostomo
- grid.255951.fHarriet L. Wilkes Honors College, Florida Atlantic University, 33458 Jupiter, FL USA
| | - Alex C. Keene
- grid.264756.40000 0004 4687 2082Department of Biology, Texas A&M, College Station, TX USA
| | - Erik R. Duboue
- grid.255951.fCharles E. Schmidt College of Science, Florida Atlantic University, 33431 Boca Raton, FL USA ,grid.255951.fHarriet L. Wilkes Honors College, Florida Atlantic University, 33458 Jupiter, FL USA
| | - Johanna E. Kowalko
- grid.259029.50000 0004 1936 746XDepartment of Biological Sciences, Lehigh University, 18015 Bethlehem, PA USA
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15
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Lloyd E, McDole B, Privat M, Jaggard JB, Duboué ER, Sumbre G, Keene AC. Blind cavefish retain functional connectivity in the tectum despite loss of retinal input. Curr Biol 2022; 32:3720-3730.e3. [PMID: 35926509 DOI: 10.1016/j.cub.2022.07.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 04/07/2022] [Accepted: 07/07/2022] [Indexed: 11/26/2022]
Abstract
Sensory systems display remarkable plasticity and are under strong evolutionary selection. The Mexican cavefish, Astyanax mexicanus, consists of eyed river-dwelling surface populations and multiple independent cave populations that have converged on eye loss, providing the opportunity to examine the evolution of sensory circuits in response to environmental perturbation. Functional analysis across multiple transgenic populations expressing GCaMP6s showed that functional connectivity of the optic tectum largely did not differ between populations, except for the selective loss of negatively correlated activity within the cavefish tectum, suggesting positively correlated neural activity is resistant to an evolved loss of input from the retina. Furthermore, analysis of surface-cave hybrid fish reveals that changes in the tectum are genetically distinct from those encoding eye loss. Together, these findings uncover the independent evolution of multiple components of the visual system and establish the use of functional imaging in A. mexicanus to study neural circuit evolution.
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Affiliation(s)
- Evan Lloyd
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Biology, Texas A&M University, College Station, TX 77843, USA; Harriet Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Brittnee McDole
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Martin Privat
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - James B Jaggard
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Erik R Duboué
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - German Sumbre
- Institut de Biologie de l'ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France.
| | - Alex C Keene
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.
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16
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Schumacher EL, Carlson BA. Convergent mosaic brain evolution is associated with the evolution of novel electrosensory systems in teleost fishes. eLife 2022; 11:74159. [PMID: 35713403 PMCID: PMC9333993 DOI: 10.7554/elife.74159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 06/16/2022] [Indexed: 11/16/2022] Open
Abstract
Brain region size generally scales allometrically with brain size, but mosaic shifts in brain region size independent of brain size have been found in several lineages and may be related to the evolution of behavioral novelty. African weakly electric fishes (Mormyroidea) evolved a mosaically enlarged cerebellum and hindbrain, yet the relationship to their behaviorally novel electrosensory system remains unclear. We addressed this by studying South American weakly electric fishes (Gymnotiformes) and weakly electric catfishes (Synodontis spp.), which evolved varying aspects of electrosensory systems, independent of mormyroids. If the mormyroid mosaic increases are related to evolving an electrosensory system, we should find similar mosaic shifts in gymnotiforms and Synodontis. Using micro-computed tomography scans, we quantified brain region scaling for multiple electrogenic, electroreceptive, and non-electrosensing species. We found mosaic increases in cerebellum in all three electrogenic lineages relative to non-electric lineages and mosaic increases in torus semicircularis and hindbrain associated with the evolution of electrogenesis and electroreceptor type. These results show that evolving novel electrosensory systems is repeatedly and independently associated with changes in the sizes of individual major brain regions independent of brain size, suggesting that selection can impact structural brain composition to favor specific regions involved in novel behaviors. Larger animals tend to have larger brains and smaller animals tend to have smaller ones. However, some species do not fit the pattern that would be expected based on their body size. This variation between species can also apply to individual brain regions. This may be due to evolutionary forces shaping the brain when favouring particular behaviours. However, it is difficult to directly link changes in species behaviour and variations in brain structure. One way to understand the impact of evolutionary adaptations is to study species that have developed new behaviours and compare them to related ones that lack such a behaviour. An opportunity to do this lies in the ability of several species of fish to produce and sense electric fields in water. While this system is not found in most fish, it has evolved multiple times independently in distantly-related lineages. Schumacher and Carlson examined whether differences in the size of brains and individual regions between species were associated with the evolution of electric field generation and sensing. Micro-computed tomography, or μCT, scans of the brains of multiple fish species revealed that the species that can produce electricity – also known as ‘electrogenic’ species’ – have more similar brain structures to each other than to their close relatives that lack this ability. The brain regions involved in producing and detecting electrical charges were larger in these electrogenic fish. This similarity was apparent despite variations in how total brain size has evolved with body size across species. These results demonstrate how evolutionary forces acting on particular behaviours can lead to predictable changes in brain structure. Understanding how and why brains evolve will allow researchers to better predict how species’ brains and behaviours may adapt as human activities alter their environments.
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Affiliation(s)
- Erika L Schumacher
- Department of Biology, Washington University in St. Louis, St. Louis, United States
| | - Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, United States
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17
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Barker AJ. Brains and speciation: Control of behavior. Curr Opin Neurobiol 2021; 71:158-163. [PMID: 34847485 DOI: 10.1016/j.conb.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/25/2021] [Accepted: 11/02/2021] [Indexed: 10/19/2022]
Abstract
As organisms invade new ecological niches, new species are formed. Simultaneously, behavioral repertoires diverge to adapt to new environments and reproductive partners. Such behavioral modifications require changes in underlying neural circuitry and thus speciation events provide a unique advantage for studying brain evolution: allowing for direct comparisons between homologous neural circuits with distinct functional outputs. Here, I will consider how speciation events can reveal common motifs within brain evolution focusing on recent research across a wide range of phyla.
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Affiliation(s)
- Alison J Barker
- Max-Planck-Institute for Brain Research, Max-Planck-Institut fur Hirnforschung, Frankfurt am Main, Germany.
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18
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Neural divergence and hybrid disruption between ecologically isolated Heliconius butterflies. Proc Natl Acad Sci U S A 2021; 118:2015102118. [PMID: 33547240 DOI: 10.1073/pnas.2015102118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The importance of behavioral evolution during speciation is well established, but we know little about how this is manifest in sensory and neural systems. A handful of studies have linked specific neural changes to divergence in host or mate preferences associated with speciation. However, the degree to which brains are adapted to local environmental conditions, and whether this contributes to reproductive isolation between close relatives that have diverged in ecology, remains unknown. Here, we examine divergence in brain morphology and neural gene expression between closely related, but ecologically distinct, Heliconius butterflies. Despite ongoing gene flow, sympatric species pairs within the melpomene-cydno complex are consistently separated across a gradient of open to closed forest and decreasing light intensity. By generating quantitative neuroanatomical data for 107 butterflies, we show that Heliconius melpomene and Heliconius cydno clades have substantial shifts in brain morphology across their geographic range, with divergent structures clustered in the visual system. These neuroanatomical differences are mirrored by extensive divergence in neural gene expression. Differences in both neural morphology and gene expression are heritable, exceed expected rates of neutral divergence, and result in intermediate traits in first-generation hybrid offspring. Strong evidence of divergent selection implies local adaptation to distinct selective optima in each parental microhabitat, suggesting the intermediate traits of hybrids are poorly matched to either condition. Neural traits may therefore contribute to coincident barriers to gene flow, thereby helping to facilitate speciation.
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19
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Schrader L, Pan H, Bollazzi M, Schiøtt M, Larabee FJ, Bi X, Deng Y, Zhang G, Boomsma JJ, Rabeling C. Relaxed selection underlies genome erosion in socially parasitic ant species. Nat Commun 2021; 12:2918. [PMID: 34006882 PMCID: PMC8131649 DOI: 10.1038/s41467-021-23178-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 04/06/2021] [Indexed: 02/03/2023] Open
Abstract
Inquiline ants are highly specialized and obligate social parasites that infiltrate and exploit colonies of closely related species. They have evolved many times convergently, are often evolutionarily young lineages, and are almost invariably rare. Focusing on the leaf-cutting ant genus Acromyrmex, we compared genomes of three inquiline social parasites with their free-living, closely-related hosts. The social parasite genomes show distinct signatures of erosion compared to the host lineages, as a consequence of relaxed selective constraints on traits associated with cooperative ant colony life and of inquilines having very small effective population sizes. We find parallel gene losses, particularly in olfactory receptors, consistent with inquiline species having highly reduced social behavioral repertoires. Many of the genomic changes that we uncover resemble those observed in the genomes of obligate non-social parasites and intracellular endosymbionts that branched off into highly specialized, host-dependent niches.
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Affiliation(s)
- Lukas Schrader
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany.
| | | | - Martin Bollazzi
- Entomología, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Morten Schiøtt
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Fredrick J Larabee
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | | | | | - Guojie Zhang
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- BGI-Shenzhen, Shenzhen, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Christian Rabeling
- Department of Biology, University of Rochester, Rochester, NY, USA.
- School of Life Sciences, Arizona State University, Tempe, AZ, USA.
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20
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Jaggard JB, Lloyd E, Yuiska A, Patch A, Fily Y, Kowalko JE, Appelbaum L, Duboue ER, Keene AC. Cavefish brain atlases reveal functional and anatomical convergence across independently evolved populations. SCIENCE ADVANCES 2020; 6:6/38/eaba3126. [PMID: 32938683 PMCID: PMC7494351 DOI: 10.1126/sciadv.aba3126] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 07/31/2020] [Indexed: 05/06/2023]
Abstract
Environmental perturbation can drive behavioral evolution and associated changes in brain structure and function. The Mexican fish species, Astyanax mexicanus, includes eyed river-dwelling surface populations and multiple independently evolved populations of blind cavefish. We used whole-brain imaging and neuronal mapping of 684 larval fish to generate neuroanatomical atlases of surface fish and three different cave populations. Analyses of brain region volume and neural circuits associated with cavefish behavior identified evolutionary convergence in hindbrain and hypothalamic expansion, and changes in neurotransmitter systems, including increased numbers of catecholamine and hypocretin/orexin neurons. To define evolutionary changes in brain function, we performed whole-brain activity mapping associated with behavior. Hunting behavior evoked activity in sensory processing centers, while sleep-associated activity differed in the rostral zone of the hypothalamus and tegmentum. These atlases represent a comparative brain-wide study of intraspecies variation in vertebrates and provide a resource for studying the neural basis of behavioral evolution.
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Affiliation(s)
- James B Jaggard
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Evan Lloyd
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Anders Yuiska
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Adam Patch
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Yaouen Fily
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Johanna E Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Lior Appelbaum
- The Faculty of Life Sciences and The Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Erik R Duboue
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA.
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21
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Chin JSR, Loomis CL, Albert LT, Medina-Trenche S, Kowalko J, Keene AC, Duboué ER. Analysis of stress responses in Astyanax larvae reveals heterogeneity among different populations. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:486-496. [PMID: 32767504 DOI: 10.1002/jez.b.22987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 11/07/2022]
Abstract
Stress responses are conserved physiological and behavioral outcomes as a result of facing potentially harmful stimuli, yet in pathological states, stress becomes debilitating. Stress responses vary considerably throughout the animal kingdom, but how these responses are shaped evolutionarily is unknown. The Mexican cavefish has emerged as a powerful system for examining genetic principles underlying behavioral evolution. Here, we demonstrate that cave Astyanax have reduced behavioral and physiological measures of stress when examined at larval stages. We also find increased expression of the glucocorticoid receptor, a repressible element of the neuroendocrine stress pathway. Additionally, we examine stress in three different cave populations, and find that some, but not all, show reduced stress measures. Together, these results reveal a mechanistic system by which cave-dwelling fish reduced stress, presumably to compensate for a predator poor environment.
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Affiliation(s)
- Jacqueline S R Chin
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Department of Biological Science, Florida Atlantic University, Jupiter, Florida
| | - Cody L Loomis
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Department of Biological Science, Florida Atlantic University, Jupiter, Florida
| | - Lydia T Albert
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Shirley Medina-Trenche
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Johanna Kowalko
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Alex C Keene
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Department of Biological Science, Florida Atlantic University, Jupiter, Florida
| | - Erik R Duboué
- Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
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22
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Abstract
The small teleost fish Astyanax mexicanus has emerged as an outstanding model for studying many biological topics in the context of evolution. A major attribute is conspecific surface dwelling (surface fish) and blind cave dwelling (cavefish) morphs that can be raised in the laboratory and spawn large numbers of transparent and synchronously developing embryos. More than 30 cavefish populations have been discovered, mostly in northeastern Mexico, and some are thought to have evolved independently from surface fish ancestors, providing excellent models of parallel and convergent evolution. Cavefish have evolved eye and pigmentation regression, as well as modifications in brain morphology, behaviors, heart regenerative capacity, metabolic processes, and craniofacial organization. Thus, the Astyanax model provides researchers with natural "mutants" to study life in the challenging cave environment. The application of powerful genetic approaches based on hybridization between the two morphs and between the different cavefish populations are key advantages for deciphering the developmental and genetic mechanisms regulating trait evolution. QTL analysis has revealed the genetic architectures of gained and lost traits. In addition, some cavefish traits resemble human diseases, offering novel models for biomedical research. Astyanax research is supported by genome assemblies, transcriptomes, tissue and organ transplantation, gene manipulation and editing, and stable transgenesis, and benefits from a welcoming and interactive research community that conducts integrated community projects and sponsors the International Astyanax Meeting (AIM).
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Affiliation(s)
- William R Jeffery
- Department of Biology, University of Maryland, College Park, MD 20742 USA
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23
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McGaugh SE, Kowalko JE, Duboué E, Lewis P, Franz-Odendaal TA, Rohner N, Gross JB, Keene AC. Dark world rises: The emergence of cavefish as a model for the study of evolution, development, behavior, and disease. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:397-404. [PMID: 32638529 DOI: 10.1002/jez.b.22978] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/24/2022]
Abstract
A central question in biology is how naturally occurring genetic variation accounts for morphological and behavioral diversity within a species. The Mexican tetra, Astyanax mexicanus, has been studied for nearly a century as a model for investigating trait evolution. In March of 2019, researchers representing laboratories from around the world met at the Sixth Astyanax International Meeting in Santiago de Querétaro, Mexico. The meeting highlighted the expanding applications of cavefish to investigations of diverse aspects of basic biology, including development, evolution, and disease-based applications. A broad range of integrative approaches are being applied in this system, including the application of state-of-the-art functional genetic assays, brain imaging, and genome sequencing. These advances position cavefish as a model organism for addressing fundamental questions about the genetics and evolution underlying the impressive trait diversity among individual populations within this species.
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Affiliation(s)
- Suzanne E McGaugh
- Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, Minnesota
| | - Johanna E Kowalko
- The Jupiter Life Science Initiative and Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Erik Duboué
- The Jupiter Life Science Initiative and Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Peter Lewis
- The Jupiter Life Science Initiative and Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida
| | | | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, Missouri
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio
| | - Alex C Keene
- The Jupiter Life Science Initiative and Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida
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24
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Maldonado E, Rangel-Huerta E, Rodriguez-Salazar E, Pereida-Jaramillo E, Martínez-Torres A. Subterranean life: Behavior, metabolic, and some other adaptations of Astyanax cavefish. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:463-473. [PMID: 32346998 DOI: 10.1002/jez.b.22948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/25/2020] [Accepted: 04/04/2020] [Indexed: 12/20/2022]
Abstract
The ability of fishes to adapt to any aquatic environment seems limitless. It is enthralling how new species keep appearing at the deep sea or in subterranean environments. There are close to 230 known species of cavefishes, still today the best-known cavefish is Astyanax mexicanus, a Characid that has become a model organism, and has been studied and scrutinized since 1936. There are two morphotypes for A. mexicanus, a surface fish and a cavefish. The surface fish lives in central and northeastern Mexico and south of the United States, while the cavefish is endemic to the "Sierra del Abra-Tanchipa region" in northeast Mexico. The extensive genetic and genomic analysis depicts a complex origin for Astyanax cavefish, with multiple cave invasions and persistent gene flow among cave populations. The surface founder population prevails in the same region where the caves are. In this review, we focus on both morphotype's main morphological and physiological differences, but mainly in recent discoveries about behavioral and metabolic adaptations for subterranean life. These traits may not be as obvious as the troglomorphic characteristics, but are key to understand how Astyanax cavefish thrives in this environment of perpetual darkness.
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Affiliation(s)
- Ernesto Maldonado
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Emma Rangel-Huerta
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Elizabeth Rodriguez-Salazar
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Elizabeth Pereida-Jaramillo
- Laboratorio de Neurobiología Molecular y Celular, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Santiago de Querétaro, México
| | - Ataulfo Martínez-Torres
- Laboratorio de Neurobiología Molecular y Celular, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Santiago de Querétaro, México
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25
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Kowalko J. Utilizing the blind cavefish Astyanax mexicanus to understand the genetic basis of behavioral evolution. J Exp Biol 2020; 223:223/Suppl_1/jeb208835. [DOI: 10.1242/jeb.208835] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ABSTRACT
Colonization of novel habitats often results in the evolution of diverse behaviors. Comparisons between individuals from closely related populations that have evolved divergent behaviors in different environments can be used to investigate behavioral evolution. However, until recently, functionally connecting genotypes to behavioral phenotypes in these evolutionarily relevant organisms has been difficult. The development of gene editing tools will facilitate functional genetic analysis of genotype–phenotype connections in virtually any organism, and has the potential to significantly transform the field of behavioral genetics when applied to ecologically and evolutionarily relevant organisms. The blind cavefish Astyanax mexicanus provides a remarkable example of evolution associated with colonization of a novel habitat. These fish consist of a single species that includes sighted surface fish that inhabit the rivers of Mexico and southern Texas and at least 29 populations of blind cavefish from the Sierra Del Abra and Sierra de Guatemala regions of Northeast Mexico. Although eye loss and albinism have been studied extensively in A. mexicanus, derived behavioral traits including sleep loss, alterations in foraging and reduction in social behaviors are now also being investigated in this species to understand the genetic and neural basis of behavioral evolution. Astyanax mexicanus has emerged as a powerful model system for genotype–phenotype mapping because surface and cavefish are interfertile. Further, the molecular basis of repeated trait evolution can be examined in this species, as multiple cave populations have independently evolved the same traits. A sequenced genome and the implementation of gene editing in A. mexicanus provides a platform for gene discovery and identification of the contributions of naturally occurring variation to behaviors. This review describes the current knowledge of behavioral evolution in A. mexicanus with an emphasis on the molecular and genetic underpinnings of evolved behaviors. Multiple avenues of new research that can be pursued using gene editing tools are identified, and how these will enhance our understanding of behavioral evolution is discussed.
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Affiliation(s)
- Johanna Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
- Program of Neurogenetics, Florida Atlantic University, Jupiter, FL 33458, USA
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