title: Sexually dimorphic gene expressions in eels: useful markers for early sex assessment in a conservation context.
abstract: Environmental sex determination (ESD) has been detected in a range of vertebrate reptile and fish species. Eels are characterized by an ESD that occurs relatively late, since sex cannot be histologically determined before individuals reach 28 cm. Because several eel species are at risk of extinction, assessing sex at the earliest stage is a crucial management issue. Based on preliminary results of RNA sequencing, we targeted genes susceptible to be differentially expressed between ovaries and testis at different stages of development. Using qPCR, we detected testis-specific expressions of dmrt1, amh, gsdf and pre-miR202 and ovary-specific expressions were obtained for zar1, zp3 and foxn5. We showed that gene expressions in the gonad of intersexual eels were quite similar to those of males, supporting the idea that intersexual eels represent a transitional stage towards testicular differentiation. To assess whether these genes would be effective early molecular markers, we sampled juvenile eels in two locations with highly skewed sex ratios. The combined expression of six of these genes allowed the discrimination of groups according to their potential future sex and thus this appears to be a useful tool to estimate sex ratios of undifferentiated juvenile eels.
authors.affiliation: INRA, UR1037 LPGP, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France.|INRA, UMR 1224 Ecobiop, Aquapôle, Pôle Gest'Aqua, Quartier Ibarron, 64310, Saint Pée sur Nivelle, France.|UPPA, UMR 1224 Ecobiop, UFR des Sciences de la Côte Basque, allée du parc Montaury, 64600, Anglet, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Geffroy
authors.affiliation: INRA, UR1037 LPGP, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France.
authors.forename: Florian
authors.initials: F
authors.lastname: Guilbaud
authors.affiliation: UMR 5110 CNRS - UPVD (CEFREM), Université de Perpignan, Bâtiment R, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France.
authors.forename: Elsa
authors.initials: E
authors.lastname: Amilhat
authors.affiliation: Onema, pôle Gest'Aqua, 65 rue de Saint Brieuc, 35042 Rennes Cedex, France.|INRA, 1224 (U3E), Pôle Gest'Aqua, 65 rue de Saint Brieuc, 35042 Rennes Cedex, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Beaulaton
authors.affiliation: INRA, UMR 1224 Ecobiop, Aquapôle, Pôle Gest'Aqua, Quartier Ibarron, 64310, Saint Pée sur Nivelle, France.|UPPA, UMR 1224 Ecobiop, UFR des Sciences de la Côte Basque, allée du parc Montaury, 64600, Anglet, France.
authors.forename: Matthias
authors.initials: M
authors.lastname: Vignon
authors.affiliation: INRA, UMR 1224 Ecobiop, Aquapôle, Pôle Gest'Aqua, Quartier Ibarron, 64310, Saint Pée sur Nivelle, France.|UPPA, UMR 1224 Ecobiop, UFR des Sciences de la Côte Basque, allée du parc Montaury, 64600, Anglet, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Huchet
authors.affiliation: INRA, UMR 1224 Ecobiop, Aquapôle, Pôle Gest'Aqua, Quartier Ibarron, 64310, Saint Pée sur Nivelle, France.|UPPA, UMR 1224 Ecobiop, UFR des Sciences de la Côte Basque, allée du parc Montaury, 64600, Anglet, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Rives
authors.affiliation: INRA, UR1037 LPGP, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Bobe
authors.affiliation: INRA, UR1037 LPGP, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Fostier
authors.affiliation: INRA, UR1037 LPGP, Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Guiguen
authors.affiliation: INRA, UMR 1224 Ecobiop, Aquapôle, Pôle Gest'Aqua, Quartier Ibarron, 64310, Saint Pée sur Nivelle, France.|UPPA, UMR 1224 Ecobiop, UFR des Sciences de la Côte Basque, allée du parc Montaury, 64600, Anglet, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Bardonnet