Therx3gene contributes to the evolution of eye loss in the cavefishAstyanax mexicanus

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 15, 2024

Abstract Uncovering mechanisms by which sensory systems evolve is critical for understanding how organisms adapt to a novel environment. Astyanax mexicanus species of fish with populations surface that inhabit rivers and streams cavefish have adapted life within caves. Cavefish evolved system changes relative their counterparts, providing an opportunity investigate underlying evolution. Here, we report the role gene retinal homeobox 3 ( rx3 ) in eye We generated putative loss-of-function mutations using CRISPR-Cas9 determine this development species. These mutant fail develop eyes, demonstrating required development. Further, exhibit altered behaviors wild-type fish, suggesting loss eyes impacts sensory-dependent behaviors. Finally, cave-surface hybrid inherit allele from siblings allele, cis-regulatory variation at locus contributes size evolution cavefish. Together, these findings demonstrate that, as other species, A. . Moreover, they suggest plays reduction cavefish, shedding light on genetic response extreme environmental changes.

Language: Английский

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

Research Square (Research Square), Journal Year: 2023, Volume and Issue: unknown

Published: July 17, 2023

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 loss-of-function mutations in previously defined sets genes, i.e., vision, circadian clock pigmentation genes — non-functional alleles four vision were identified. Then, genome-wide these populations. Among 512 with segregating alleles, found an enrichment visual perception genes. populations, different levels shared found. a subset 12 which found, extend analysis pseudogenes to 11 six del Toro population, where extensive hybridization surface fish occurs, correlation between level eye regression amount alleles. Conclusions We can confirm very few are present large set accordance recent origin cavefish. Nevertheless, indicates vision-related GO-terms, suggesting may be function chiefly impacted by gene losses related shift environment. The geographic distribution supports hypothesis Sierra Guatemala Abra share common origin, albeit followed independent evolution long period time. It also Micos area have origin. In Toro, troglomorphic phenotype is maintained despite massive introgression genome.

Language: Английский

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Evolution of olfactory sensitivity, preferences and behavioral responses in Mexican cavefish: fish personality matters

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 2, 2023

Abstract Animals are adapted to their natural habitats and lifestyles. Their brains perceive the external world via sensory systems, compute information together with that of internal states autonomous activity, generate appropriate behavioral outputs. However, how do these processes evolve across evolution? Here, focusing on sense olfaction, we have studied evolution in olfactory sensitivity, preferences responses six different food-related amino acid odors two eco-morphs fish Astyanax mexicanus . To this end, developed a high-throughput setup pipeline quantitative qualitative behavior analysis, tested 489 six-week-old larvae. The blind, dark-adapted morphs species showed markedly distinct basal swimming patterns odors, higher sensitivity strong preference for alanine, as compared river-dwelling eyed conspecifics. In addition, discovered an individual “swimming personality”, personality influences capability respond efficiently find source. Importantly, traits favored significant were surface cavefish. Moreover, displayed by second-generation cave x F2 hybrids suggested olfactory-driven is genetic trait. Our findings show processing has rapidly evolved cavefish at several levels: detection threshold, odor preference, foraging strategy. Cavefish therefore outstanding model understand genetic, molecular neurophysiological basis specialization response environmental change.

Language: Английский

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The evolution of olfactory sensitivity, preferences, and behavioral responses in Mexican cavefish is influenced by fish personality

eLife, Journal Year: 2023, Volume and Issue: 12

Published: Dec. 19, 2023

Animals are adapted to their natural habitats and lifestyles. Their brains perceive the external world via sensory systems, compute information together with that of internal states autonomous activity, generate appropriate behavioral outputs. However, how do these processes evolve across evolution? Here, focusing on sense olfaction, we have studied evolution in olfactory sensitivity, preferences, responses six different food-related amino acid odors two eco-morphs fish Astyanax mexicanus . To this end, developed a high-throughput setup pipeline quantitative qualitative behavior analysis, tested 489 six-week-old larvae. The blind, dark-adapted morphs species showed markedly distinct basal swimming patterns odors, higher strong preference for alanine, as compared river-dwelling eyed conspecifics. In addition, discovered an individual ‘swimming personality’, personality influences capability respond efficiently find source. Importantly, traits favored significant were surface cavefish. Moreover, displayed by second-generation cave × F2 hybrids suggested olfactory-driven sensitivity is genetic trait. Our findings show processing has rapidly evolved cavefish at several levels: detection threshold, odor preference, foraging strategy. Cavefish therefore outstanding model understand genetic, molecular, neurophysiological basis specialization response environmental change.

Language: Английский

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Cavefish focus on which way the water flows

Journal of Experimental Biology, Journal Year: 2022, Volume and Issue: 225(19)

Published: Oct. 1, 2022

People tend to rely on their eyes understand the world, but some fish don't have or even light for illumination. A population of Astyanax mexicanus, ‘cavefish’, thrive deep in caves where they navigate and find food total darkness. team researchers based at University Florida, USA, led by James Liao, looked beyond this obvious difference hidden mechanisms behind cavefish's success exploring world without eyes. They wanted know if cavefish nervous system adjusted lack amplifying other senses, specifically sense ‘touch’, which detects water flow through structures called neuromasts distributed across fish's body. The compared how differ between blind another sighted A. live streams surface planet use explore.Instead comparing adult responded flowing water, larval from each species rule out possibility that any differences were due learning as developed. found distribution along sides larvae differs two populations: more closer heads than a river surface. However, neuromast was made up similar number flow-sensitive hairs get tugged moves past them – hair cells our inner ears, air pressure changes allow us perceive sound.To determine whether also adapted dark environment, measured electrical signals produced single sensory when still. When not swimming, stronger those relatives, indicating baseline communication brain is higher. In addition, vibrated mimic past, response again fish.The then determined communicated while simulated swimming. By recording neuromasts, are relay fewer still, allows ignore body generating own movement. continued swimming.Next, tested sensitivity swim dictated brain. located neurons send sensors experimentally silenced neurons. Without brain, surface-dwelling relayed similarly cavefish: be active Suppressing during swimming can lead efficient dwellers, cavefish, sensitive likely beneficial. And, populations cave systems, systems both adopted strategy increase swimming.Fish with sight eyes, feel way continuing signal waterflow This extra attention requires energy, it's worth cost

Language: Английский

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