Biology subjects

Hyacinthe, C.

Publications and source records attributed to Hyacinthe, C..

3 recordsLinked to original sources

bioRxiv2022

Genetic identification and reiterated captures suggests that the Astyanax mexicanus El Pachon cavefish population is closed and declining

The size of Astyanax mexicanus blind cavefish populations of North-East Mexico is a demographic parameter of great importance for investigating a variety of ecological, evolutionary and conservation issues. However, very few estimates have been obtained. For these mobile animals living in an environment difficult to explore as a whole, methods based on capture-mark-recapture are appropriate, but the feasibility of such approach and the interpretation of the results depend on several assumptions that must be carefully examined. Here, we provide evidence that minimally invasive genetic identification from captures at different time intervals can give insights on cavefish population size dynamics as well as other important demographic parameters of interest. We also provide tools to calibrate sampling and genotyping efforts necessary to reach a given level of precision. Our results suggest that the El Pachon cave population is currently very small, of an order of magnitude of a few hundreds of individuals, and is distributed in a relatively isolated area. The probable decline in population size in the El Pachon cave since the last census in 1971 raises serious conservation issues.

zoology↗

bioRxiv2022

Genetic mapping of craniofacial traits in the Mexican tetra reveals loci associated with bite differences between cave and surface fish

The Mexican tetra, Astyanax mexicanus, includes interfertile surface-dwelling and cave-dwelling morphs, enabling powerful studies aimed at uncovering genes involved in the evolution of cave-associated traits. Compared to surface fish, cavefish harbor several extreme traits within their skull, such as a protruding lower jaw, a wider gape, and an increase in tooth number. These features are highly variable between individual cavefish and even across different cavefish populations. To investigate these traits, we created a novel feeding behavior assay wherein bite impressions could be obtained. We determined that fish with an underbite leave larger bite impressions with an increase in the number of tooth marks. Capitalizing on the ability to produce hybrids from surface and cavefish crosses, we investigated genes underlying these segregating orofacial traits by performing Quantitative Trait Loci (QTL) analysis with F2 hybrids. We discovered significant QTL for bite (underbite vs. overbite) that mapped to a single region of the Astyanax genome. This work highlights cavefish as a valuable genetic model for orofacial patterning and will provide insight into the genetic regulators of jaw and tooth development.

evolutionary biology↗

bioRxiv2022

Acoustic signatures in cavefish populations inhabiting different caves

Complex patterns of acoustic communication exist throughout the animal kingdom, including underwater. The river-dwelling and the Pachon cave-adapted morphs of the fish Astyanax mexicanus share a repertoire of sounds, but their trigger, use and meaning has changed in cavefish after their recent colonization of the subterranean environment. Here, we explored whether and how sounds produced by blind cavefishes inhabiting different Mexican caves may have evolved, too. We compared acoustic parameters of sounds produced by wild cavefish, recorded in their natural settings, in six different caves located in three mountains ranges in North-East Mexico. Multi-parametric analyses show that the six cavefish populations sampled present cave-specific acoustic signatures, as well as possible individual signatures. The variations in acoustic parameters do not seem related to fish phenotypes, phylogeography or ecological conditions. We propose that the evolution of such acoustic signatures would be neutral and occur by drift, progressively leading to the differentiation of local accents that may prevent interbreeding and thus contribute to speciation.

animal behavior and cognition↗