Spatially varying natural selection in a fish hybrid zone |
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Authors: | L Crespin †‡ P Berrebi § J-D Lebreton † |
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Institution: | Laboratoire Génome et Populations, UPR 9060 UniversitéMontpellier II cc063, Place Eugène Bataillon, 34095 Montpellier cedex 5, France;CEFE CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France |
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Abstract: | A capture-mark-recapture (CMR) study in a hybrid zone between two species of barbel, Barbus barbus and Barbus meridionalis , in the Lergue River (southern France) failed to reject the null hypothesis of no difference in survival among phenotypes. Power calculations indicated that very intensive fieldwork should be carried out if this hypothesis was to be investigated again. The study demonstrated, however, that there were marked differences in survival between upstream and downstream sites. It is suggested that there is an environmental gradient of selection along the hybrid zone (extrinsic component of natural selection). |
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Keywords: | hybrid zone natural selection Barbus survival capture-mark-recapture |
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