Unraveling stress resilience: Insights from adaptations to extreme environments by Astyanax mexicanus cavefish

Journal of Experimental Zoology Part B Molecular and Developmental Evolution, Journal Year: 2024, Volume and Issue: 342(3), P. 178 - 188

Published: Jan. 21, 2024

Abstract Extreme environmental conditions have profound impacts on shaping the evolutionary trajectory of organisms. Exposure to these elicits stress responses, that can trigger phenotypic changes in novel directions. The Mexican Tetra, Astyanax mexicanus , is an excellent model for understanding mechanisms response extreme or new environments. This fish species consists two morphs; classical surface‐dwelling and blind cave‐dwellers inhabit dark biodiversity‐reduced ecosystems. In this review, we explore specific stressors present cave environments examine diverse adaptive strategies employed by populations not only survive but thrive as successful colonizers. By analyzing responses A. gain valuable insights into genetic, physiological, behavioral adaptations enable organisms flourish under challenging conditions.

Language: Английский

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Expanding evolutionary neuroscience: insights from comparing variation in behavior

Neuron, Journal Year: 2021, Volume and Issue: 109(7), P. 1084 - 1099

Published: Feb. 21, 2021

Neuroscientists have long studied species with convenient biological features to discover how behavior emerges from conserved molecular, neural, and circuit level processes. With the advent of new tools, viral vectors gene editing automated behavioral analyses, there has been a recent wave interest in developing new, "nontraditional" model species. Here, we advocate for complementary approach development, that is, clade as way integrate an evolutionary comparative neurobiological experiments. Capitalizing on natural variation investing experimental tools clades will be valuable strategy next generation neuroscience discovery.

Language: Английский

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Whole-brain optical access in a small adult vertebrate with two- and three-photon microscopy

iScience, Journal Year: 2022, Volume and Issue: 25(10), P. 105191 - 105191

Published: Sept. 23, 2022

Language: Английский

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A connectomics-based taxonomy of mammals

eLife, Journal Year: 2022, Volume and Issue: 11

Published: Nov. 7, 2022

Mammalian taxonomies are conventionally defined by morphological traits and genetics. How species differ in terms of neural circuits whether inter-species differences circuit organization conform to these is unknown. The main obstacle the comparison architectures has been network reconstruction techniques, yielding species-specific connectomes that not directly comparable one another. Here, we comprehensively chart connectome across mammalian phylogenetic spectrum using a common protocol. We analyse MRI (MaMI) data set, database encompasses high-resolution ex vivo structural diffusion scans 124 12 taxonomic orders 5 superorders, collected unified assess similarity between two methods: Laplacian eigenspectra multiscale topological features. find greater similarities among within same order, suggesting reflects established relationships morphology While all retain hallmark global features relative proportions connection classes, variation driven local regional connectivity profiles. By encoding into frame reference, findings establish foundation for investigating how change over phylogeny, forging link from genes behaviour.

Language: Английский

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Kinematic analysis of social interactions deconstructs the evolved loss of schooling behavior in cavefish

PLoS ONE, Journal Year: 2022, Volume and Issue: 17(4), P. e0265894 - e0265894

Published: April 6, 2022

Fish display a remarkable diversity of social behaviors, both within and between species. While behaviors are likely critical for survival, surprisingly little is known about how they evolve in response to changing environmental pressures. With its highly surface form multiple populations largely asocial, blind, cave-dwelling form, the Mexican tetra, Astyanax mexicanus , provides powerful model study evolution behavior. Here we use motion tracking analysis swimming kinematics quantify four populations. In light, fish school, maintaining close proximity alignment with each other. dark, no longer coherent schools, however, still show evidence an attempt align maintain when find themselves near another fish. contrast, cavefish from three independently-evolved (Pachón, Molino, Tinaja) preference or alignment, instead exhibiting that suggest active avoidance Two cave studied also slow down more present tank, behavior which not observed light suggesting divergent responses conspecifics. Using data-driven computer simulations, reduction speed sufficient alter way explore their environment: it can increase time spent exploring away walls. Thus, absence schooling merely consequence inability see, but may rather be genuine behavioral adaptation impacts environment.

Language: Английский

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The nature and distribution of putative non-functional alleles suggest only two independent events at the origins of Astyanax mexicanus cavefish populations

BMC Ecology and Evolution, Journal Year: 2024, Volume and Issue: 24(1)

Published: April 1, 2024

Abstract Background Several studies suggested that cavefish populations of Astyanax mexicanus settled during the Late Pleistocene. This implies cavefish’s most conspicuous phenotypic changes, blindness and depigmentation, more cryptic characters important for cave life, evolved rapidly. Results Using published genomes 47 from la Cueva de El Pachón, Sótano Tinaja, La Chica Molino, we searched putative loss-of-function mutations in previously defined sets genes, i.e. , vision, circadian clock pigmentation genes. Putative non-functional alleles four vision genes were identified. Then, genome-wide these populations. Among 512 with segregating are absent surface fish, found an enrichment visual perception populations, different levels shared found. a subset 12 which found, extend analysis pseudogenes to 11 six del Toro population, where extensive hybridization fish occurs, correlation between level eye regression amount alleles. Conclusions We confirm very few present large set accordance recent origin cavefish. Furthermore, indicates vision-related GO-terms, suggesting may be function chiefly impacted by gene losses related shift environment. The geographic distribution newly suggests Sierra Guatemala Abra share common origin, albeit followed independent evolution long period. It also supports Micos area have origin. In Toro, troglomorphic phenotype is maintained despite massive introgression genome.

Language: Английский

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Blind cavefish retain functional connectivity in the tectum despite loss of retinal input

Current Biology, Journal Year: 2022, Volume and Issue: 32(17), P. 3720 - 3730.e3

Published: Aug. 4, 2022

Sensory systems display remarkable plasticity and are under strong evolutionary selection. The Mexican cavefish, Astyanax mexicanus, consists of eyed river-dwelling surface populations multiple independent cave that have converged on eye loss, providing the opportunity to examine evolution sensory circuits in response environmental perturbation. Functional analysis across transgenic expressing GCaMP6s showed functional connectivity optic tectum largely did not differ between populations, except for selective loss negatively correlated activity within cavefish tectum, suggesting positively neural is resistant an evolved input from retina. Furthermore, surface-cave hybrid fish reveals changes genetically distinct those encoding loss. Together, these findings uncover components visual system establish use imaging A. mexicanus study circuit evolution.

Language: Английский

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Label‐free, whole‐brain in vivo mapping in an adult vertebrate with third harmonic generation microscopy

The Journal of Comparative Neurology, Journal Year: 2024, Volume and Issue: 532(4)

Published: April 1, 2024

Abstract Comprehensive understanding of interconnected networks within the brain requires access to high resolution information large field views and over time. Currently, methods that enable mapping structural changes entire in vivo are extremely limited. Third harmonic generation (THG) can resolve myelinated structures, blood vessels, cell bodies throughout without need for any exogenous labeling. Together with deep penetration long wavelengths, this enables brain‐mapping fractions small animals Here, we demonstrate THG microscopy allows non‐invasive label‐free an adult vertebrate, Danionella dracula , which is a miniature species cyprinid fish. We show capability multiple regions particular identification major commissural fiber bundles midbrain hindbrain. These features provide readily discernable landmarks navigation regional‐specific neuronal groups even single neurons during experiments. further how technique easily be coupled fluorescence used as comparative tool studies other similar body such zebrafish ( Danio rerio) tetras Trochilocharax ornatus ). This new evidence, building on previous studies, demonstrates size relative transparency, combined unique capabilities microscopy, vertebrate brain.

Language: Английский

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Elevated DNA Damage without signs of aging in the short-sleeping Mexican Cavefish

Published: Feb. 10, 2025

Dysregulation of sleep has widespread health consequences and represents an enormous burden. Short-sleeping individuals are predisposed to the effects neurodegeneration, suggesting a critical role for in maintenance neuronal health. While on cellular function not completely understood, growing evidence identified association between loss DNA damage, raising possibility that facilitates efficient repair. The Mexican tetra fish, Astyanax mexicanus provides model investigate evolutionary basis changes loss. Multiple cave-adapted populations these fish have evolved substantially less time compared surface same species without identifiable impacts healthspan or longevity. To whether is associated with damage stress, we Damage Response (DDR) oxidative stress levels A. populations. We measured markers chronic discovered elevated marker γH2AX brain, increased gut cavefish, consistent deprivation. Notably, found acute UV-induced elicited increase but cavefish. On transcriptional level, only activated photoreactivation repair pathway following UV damage. These findings suggest reduction DDR cavefish coincides examine pathways at created embryonic fibroblast cell line from two . observed both were diminished cells, corroborating vivo response lost long-term impact changes, transcriptome brain aged Strikingly, many genes differentially expressed young old do transcriptionally vary by age Taken together, developed resilience loss, despite possessing hallmarks

Language: Английский

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Label‐Free Multiphoton Imaging Reveals Volumetric Shifts Across Development in Sensory‐Related Brain Regions of a Miniature Transparent Vertebrate

The Journal of Comparative Neurology, Journal Year: 2025, Volume and Issue: 533(4)

Published: April 1, 2025

ABSTRACT Animals integrate information from different sensory modalities as they mature and perform increasingly complex behaviors. This may parallel differential investment in specific brain regions depending on the changing demands of inputs. To investigate developmental changes volume canonical regions, we used third harmonic generation imaging for morphometric analysis forebrain midbrain larval through juvenile adult stages Danionella dracula , a transparent, miniature teleost fish whose is optically accessible throughout its lifespan. Relative to whole‐brain volume, increased or telencephalon, higher order integration center, shows most dramatic increases between 30–60 days postfertilization (dpf) again at 90 dpf animals reach adulthood. The torus longitudinalis (TL), visuomotor also significantly 60 dpf. In contrast, optic tectum (TeO), retinal‐recipient target, progressively decreases 30 dpf, whereas relatively consistent across all semicircularis (TS), secondary auditory mechanosensory lateral line olfactory bulb (OB), direct target epithelium. sum, higher‐order centers (telencephalon, TL) occurs juveniles adulthood (60–90 dpf) exhibit more cognitive tasks, modality‐dominant earlier (TeO) development (TS, OB). Complete optical access ’s lifespan provides unique opportunity how structure over correlates with connectivity, microcircuitry, behavior.

Language: Английский

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