Locally adapted fish populations maintain small-scale genetic differentiation despite perturbation by a catastrophic flood event

  • Background: Local adaptation to divergent environmental conditions can promote population genetic differentiation even in the absence of geographic barriers and hence, lead to speciation. Perturbations by catastrophic events, however, can distort such parapatric ecological speciation processes. Here, we asked whether an exceptionally strong flood led to homogenization of gene pools among locally adapted populations of the Atlantic molly (Poecilia mexicana, Poeciliidae) in the Cueva del Azufre system in southern Mexico, where two strong environmental selection factors (darkness within caves and/or presence of toxic H2S in sulfidic springs) drive the diversification of P. mexicana. Nine nuclear microsatellites as well as heritable female life history traits (both as a proxy for quantitative genetics and for trait divergence) were used as markers to compare genetic differentiation, genetic diversity, and especially population mixing (immigration and emigration) before and after the flood. Results: Habitat type (i.e., non-sulfidic surface, sulfidic surface, or sulfidic cave), but not geographic distance was the major predictor of genetic differentiation. Before and after the flood, each habitat type harbored a genetically distinct population. Only a weak signal of individual dislocation among ecologically divergent habitat types was uncovered (with the exception of slightly increased dislocation from the Cueva del Azufre into the sulfidic creek, El Azufre). By contrast, several lines of evidence are indicative of increased flood-induced dislocation within the same habitat type, e.g., between different cave chambers of the Cueva del Azufre. Conclusions: The virtual absence of individual dislocation among ecologically different habitat types indicates strong natural selection against migrants. Thus, our current study exemplifies that ecological speciation in this and other systems, in which extreme environmental factors drive speciation, may be little affected by temporary perturbations, as adaptations to physico-chemical stressors may directly affect the survival probability in divergent habitat types.

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Author:Martin PlathORCiDGND, Bernd Hermann, Christiane Schröder, Rüdiger RieschORCiD, Michael Tobler, Francisco J. Garcia de Leon, Ingo Schlupp, Ralph Tiedemann
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/20731863
Parent Title (English):BMC evolutionary biology
Publisher:BioMed Central ; Springer
Place of publication:London ; Berlin ; Heidelberg
Document Type:Article
Date of Publication (online):2010/09/16
Date of first Publication:2010/08/23
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2010/09/16
Issue:Art. 256
Page Number:19
First Page:1
Last Page:19
© 2010 Plath et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Source:BMC Evolutionary Biology 2010, 10:256 ; doi:10.1186/1471-2148-10-256 ; http://www.biomedcentral.com/1471-2148/10/256/
Institutes:Biowissenschaften / Institut für Ökologie, Evolution und Diversität
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 59 Tiere (Zoologie) / 590 Tiere (Zoologie)
Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung 2.0