Biology subjects

Rodriguez-Morales, R.

Publications and source records attributed to Rodriguez-Morales, R..

4 recordsLinked to original sources

bioRxiv2025

Analysis of multi-trait evolution across independently evolved cavefish populations reveals shared and independent evolution of suites of cave-associated traits

Environmental perturbations often lead to the evolution of multiple traits. Determining whether shared genetic factors underlie multi-trait evolution is a central question in evolutionary biology. In the Mexican tetra, Astyanax mexicanus, cave-dwelling populations have repeatedly evolved multiple traits. The repeated evolution of these traits, paired the robust environmental differences between the surface and cave habitats, provide an opportunity to investigate the genetic basis of multi-trait evolution. Here, we investigate the extent to which shared genetic mechanisms underlie the repeated evolution of multiple traits in cavefish. Across cave populations, we find evidence for shared and distinct genetic mechanisms contributing to the evolution of individual traits. Further, multiple traits covary in cave-surface F2 hybrids and many of the same trait correlations are found across independently evolved cave populations. Finally, we assessed traits that differ between pigmented and albino F2 fish in surface fish with mutations in the albinism gene oculocutaneous albinism 2 (oca2). This revealed that mutations in oca2 reduce bottom-dwelling behavior in A. mexicanus. Together, these findings suggest that multi-trait evolution occurs repeatedly through shared genetic factors across A. mexicanus cave populations. These results are consistent with pleiotropy or linkage playing a large role in multi-trait evolution in this species.

evolutionary biology↗

bioRxiv2022

Convergence on reduced aggression through shared behavioral traits in multiple populations of Astyanax mexicanus

Aggression is a complex behavior that is observed across the animal kingdom, and plays roles in resource acquisition, defense, and reproductive success. While there are many individual differences in propensity to be aggressive within and between populations, the mechanisms underlying differences in aggression between individuals in natural populations are not well understood. We addressed this using the Mexican tetra, Astyanax mexicanus, a powerful model organism to understand behavioral evolution. A. mexicanus exists in two forms: a river-dwelling surface form and multiple populations of a blind cave form. We characterized aggression in surface fish and cavefish in a resident/intruder assay through quantifying multiple behaviors occurring during social interactions. Surface fish, which are aggressive, display multiple social behaviors in this context, which we characterized into two types of behaviors: aggression- associated and escape-associated behaviors. The majority of these behaviors were reduced or lost in Pachon cavefish. Further, both aggression-associated and escape-associated behaviors were not dependent on the presence of light, and both surface fish and cavefish remained aggressive or non-aggressive, respectively, when opposed to fish from a different population. Additionally, we found that within populations, levels of stress response were not correlated with aggression- or escape-associated behaviors. Finally, when we compared aggression- and escape- associated behaviors across four cavefish populations, we found that both types of behaviors are reduced in three cave populations, while still present in one. Together, these results reveal that multiple cavefish populations have repeatedly evolved reduced aggression through shared behavioral components, while other cavefish have retained aggression. Summary StatementComparison of aggression between surface fish and cavefish demonstrates that multiple complex behaviors compose aggression in surface fish and reveals heterogeneity in loss of aggression in cave populations.

evolutionary biology↗

bioRxiv2020

Cnr2 is important for Ribbon Synapse Maturation and Function in Hair Cells and Photoreceptors

The role of the cannabinoid receptor 2 (CNR2) is still poorly described in sensory epithelia. We found strong cnr2 expression in hair cells (HCs) of the inner ear and the lateral line (LL), a superficial sensory structure in fish. Next, we demonstrated that sensory synapses in HCs were severely perturbed in zebrafish larvae lacking cnr2. Appearance and distribution of presynaptic ribbons and calcium channels (Cav1.3) were profoundly altered in mutant animals. Clustering of membrane-associated guanylate kinase (MAGUK) in post-synaptic densities (PSDs) was also heavily affected, suggesting a role for cnr2 for maintaining the structure of the sensory synapse. Furthermore, vesicular trafficking in HCs was strongly perturbed suggesting a retrograde action of the endocannabinoid system (ECs) mediated via cnr2 that was modulating HC mechanotransduction. We found similar perturbations in retinal ribbon synapses. Finally, we showed that larval swimming behaviors after sound and light stimulations were significantly different in mutant animals. Thus, we propose that cnr2 is critical for the processing of sensory information in the developing larva.

neuroscience↗

bioRxiv2019

Valeriana Officinalis Crude Extracts Impair Hair Cell Regeneration in Larval Zebrafish Lateral Line

Irreversible hair cell (HC) loss in the inner ear is the leading cause for hearing and balance disorders. Discovery of therapeutic molecules preventing HC death and promoting regeneration, which does not occur in mammals like it does in lower vertebrates, is of major interest. In fish, HCs are also found in a superficial mechano-sensory organ called the lateral line (LL). LL-HCs are exposed to surrounding waters and are accessible to waterborne molecules providing a potent mean to study in vivo HC stability and regeneration. Commercial small molecule libraries were tested in screens for HC survival and regeneration in zebrafish, but ethnobotanical pharmacopeias remain totally unexplored because of the challenge that such complex mixtures represent. A rapid and cost-effective first-pass assay informing about the regenerative potential of an extract is therefore critical before embarking on cumbersome purification steps. We chose to test Valerian crude root extracts (Val), which are typically composed of more than 150 different components, amongst which is a main and abundant compound: valeric acid (VA). VA discovery and purification led to the commercialization of a synthetic analog: Valproic acid (VPA) which is a first-line drug for epilepsy and bipolar disorders that was also shown to significantly hamper LL-HC regeneration. We reasoned that if Val is not toxic, it would elicit effects like VPA. Thus, we synchronously ablated HCs in 5-day post-fertilization (dpf) larvae and monitored regeneration over the following 3 days in the presence of Val at the highest well-tolerated concentration (Val1 = 1mg/ml), or VPA (= 150M) as previously published. Both treatments significantly decreased HC regeneration without affecting HC-survival suggesting a similar mode of action. Furthermore, Val application as early as 3dpf and prolonged for up to 4 days did not affect larval survival, indicating that reduced HC-regeneration was not due to overall toxicity. Taken together, Val and VPA-treatments displayed a comparable response in a simple and up-scalable HC-regeneration assay which is an in-first-pass potent approach for drug discovery.

pharmacology and toxicology↗