# Characterization of the sex determining system(s) of the Mexican tetra, Astyanax mexicanus

Boudjema Imarazene, Séverine Beille, Elodie Jouanno, Romain Feron, Celine Lopez-Roques, Hugues Parrinello, Laurent Journot, Christophe C. Kropp, Julie Perez, Frédéric Veyrunes, et al.

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## ► To cite this version:

Boudjema Imarazene, Séverine Beille, Elodie Jouanno, Romain Feron, Celine Lopez-Roques, et al.. Characterization of the sex determining system(s) of the Mexican tetra, Astyanax mexicanus. Paradigm shift in sex chromosome evolution, Sep 2019, Berlin, Germany., pp.8-9, 2019, Workshop: Paradigm shift in sex chromosome evolution. 10.4126/FRL01-006417884. hal-02418501

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Distributed under a Creative Commons Attribution 4.0 International License
Boudjema Imarazene<fnref n="1" />,<fnref n="2" />, Séverine Beille<fnref n="1" />, Elodie Jouano<fnref n="1" />, Romain Feron<fnref n="1" />, Céline Lopez-Roques<fnref n="3" />, Hugues Parrinello<fnref n="4" />, Laurent Journot<fnref n="4" />, Christophe Klopp<fnref n="5" />, Julie Perez<fnref n="6" />, Frédéric Veyrunes<fnref n="6" />, John H. Postlethwait<fnref n="7" />, Manfred Schartl<fnref n="8" />, Amaury Herpin<fnref n="1" />, Sylvie Retaux<fnref n="2" />, Yann Guiguen<fnref n="1" />.

**Characterization of the sex determining system(s) of the Mexican tetra, *Astyanax mexicanus*.

In vertebrates, a remarkable diversity of sex determining mechanisms is observed, ranging from environmental to genetic sex determination (ESD and GSD). In teleosts, sex determination mechanisms include both environmental and genetic regulation and are extremely diverse, changeable, and labile. In addition, many sex-determining genes have been already found in this group of vertebrates showing that sex determination genes can be extremely variable even between closely related organisms. Hence, teleost fish have emerged as interesting models to study the macroevolution of sex determining mechanisms within vertebrates.

The cavefish Astyanax mexicanus belongs to the Characiform group. Different populations of A. mexicanus have been described, including pigmented river-dwelling and several depigmented blind cave populations. These populations are still inter-fertile and cave populations are known to have evolved from an ancestral surface population less than 100,000 years ago. In addition, these Astyanax populations can be also reared under laboratory conditions quite easily and are amenable to genetic manipulations. Altogether this makes surface and cave populations a particularly interesting evolutionary genetic model system for comparative and microevolution studies. We thus initiated studies on the evolution of sex determination and sex determining genes in *A. mexicanus* using restriction site-associated DNA sequencing (RAD-Seq) and Pool-sequencing (Pool-Seq) approaches to identify sex-biased molecular markers in both cavefish originating from the Pachón cave and surface fish populations.

Our first results led to the identification of a XX/XY sex determination system and a candidate master sex-determining gene in the Pachón cave population. But surprisingly this sex determination system is not completely conserved in the surface population as we found in this population a very strong but not complete sex linkage

<footnote n="1">¹ INRA, Fish Physiology and Genomics Laboratory, 35042 Rennes, France.</footnote>

<footnote>Corr. author's email: yann.guiguen@inra.fr</footnote>

<footnote n="2">² CNRS, UPR3294, N&D laboratory, DECA group, 91198 Gif sur Yvette, France.</footnote>

<footnote n="3">³ Getplage INRA, US 1426, GeT-PlaGe, Genotoul, Castanet-Tolosan, France.</footnote>

<footnote n="4">⁴ Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, F-34094 Montpellier, France.</footnote>

<footnote n="5">⁵ SIGENAE, GenPhySE, Université de Toulouse, INRA, ENVT, Castanet Tolosan, France.</footnote>

<footnote n="6">⁶ Institut des Sciences de l'Evolution de Montpellier (ISEM), Université de Montpellier, 34095 Montpellier, France.</footnote>

<footnote n="7">⁷ Institute of Neuroscience, University of Oregon, Eugene, USA.</footnote>

<footnote n="8">⁸ Department of Physiological Chemistry, University of Wuerzburg, Wuerzburg, Germany.</footnote>
# Paradigm shift in sex chromosome evolution

Abstracts of the workshop held in Berlin, 19-22 September 2019

## Edited by

Matthias Stöck<fnref n="1" /> https://orcid.org/0000-0003-4888-8371

Lukáš Kratochvíl<fnref n="2" /> https://orcid.org/0000-0002-3515-729X

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<footnote n="1">¹ Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Ecophysiology and Aquaculture, Berlin, Germany</footnote>

<footnote n="2">² Charles University, Faculty of Science, Department of Ecology, Prague, Czech Republic</footnote>