title: Differences in brain gene transcription profiles advocate for an important role of cognitive function in upstream migration and water obstacles crossing in European eel.
abstract: BACKGROUND
  European eel is a panmictic species, whose decline has been recorded since the last 20 years. Among human-induced environmental factors of decline, the impact of water dams during species migration is questioned. The main issue of this study was to pinpoint phenotypic traits that predisposed glass eels to successful passage by water barriers. The approach of the study was individual-centred and without any a priori hypothesis on traits involved in the putative obstacles selective pressure. We analyzed the transcription level of 14,913 genes.
  
  
  RESULTS
  Transcriptome analysis of three tissues (brain, liver and muscle) from individuals sampled on three successive forebays separated by water obstacles indicated different gene transcription profiles in brain between the two upstream forebays. No differences in gene transcription levels were observed in liver and muscle samples among segments. A total of 26 genes were differentially transcribed in brain. These genes encode for, among others, keratins, cytokeratins, calcium binding proteins (S100 family), cofilin, calmodulin, claudin and thy-1 membrane glycoprotein. The functional analysis of these genes highlighted a putative role of cytoskeletal dynamics and synaptic plasticity in fish upstream migration.
  
  
  CONCLUSIONS
  Synaptic connections in brain are solicited while eels are climbing the obstacles with poorly designed fishways. Successful passage by such barriers can be related to spatial learning and spatial orientation abilities when fish is out of the water.
authors.affiliation: Irstea Bordeaux, UR EABX, HYNES (Irstea - EDF R&D), 50 avenue de Verdun, Cestas, 33612, Cedex, France. tomasz.podgorniak@irstea.fr.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Podgorniak
authors.affiliation: University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy. massimo.milan@unipd.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Milan
authors.affiliation: University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy. martipujolar@gmail.com.|Department of Bioscience, Aarhus University, Ny Munkegade 114, Aarhus C, DK-8000, Denmark. martipujolar@gmail.com.
authors.forename: Jose Marti
authors.initials: JM
authors.lastname: Pujolar
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture, Comparative Genomics Centre, College of Marine and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia. Gregory.Maes@bio.kuleuven.be.|Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven (KU Leuven), Leuven, B-3000, Belgium. Gregory.Maes@bio.kuleuven.be.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Maes
authors.affiliation: University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy. luca.bargelloni@unipd.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Bargelloni
authors.affiliation: EDF R&D LNHE, HYNES (Irstea-EDF R&D), 6, quai Watier, Bat Q, Chatou, 78400, France. eric.de-oliveira@edf.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: De Oliveira
authors.affiliation: Univ. Bordeaux, EPOC, UMR 5805, Talence, F-33400, France. f.pierron@epoc.u-bordeaux1.fr.|CNRS, EPOC, UMR 5805, Talence, F-33400, France. f.pierron@epoc.u-bordeaux1.fr.
authors.forename: Fabien
authors.initials: F
authors.lastname: Pierron
authors.affiliation: Irstea Bordeaux, UR EABX, HYNES (Irstea - EDF R&D), 50 avenue de Verdun, Cestas, 33612, Cedex, France. francoise.daverat@irstea.fr.
authors.forename: Francoise
authors.initials: F
authors.lastname: Daverat
mesh_terms: D000811:Anguilla; D025041:Animal Migration; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D003071:Cognition; D020869:Gene Expression Profiling; D020411:Oligonucleotide Array Sequence Analysis; D009928:Organ Specificity; D014158:Transcription, Genetic; D014867:Water
chemical_list: D014867:Water