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A Selective Advantage to Immigrant Genes in a Daphnia Metapopulation
Dieter Ebert,123*Christoph Haag,123*Mark Kirkpatrick,4Myriam Riek,12Jürgen W. Hottinger,123V. Ilmari Pajunen25
Immigrants to habitats occupied by conspecific organisms are
usually expected to be competitively inferior, because residentsmay be
locally adapted. If residents are inbred, however, matingbetween
immigrants and residents results in offspring that mayenjoy a fitness
advantage from hybrid vigor. We demonstrate thiseffect experimentally
in a natural Daphnia metapopulation in whichgenetic
bottlenecks and local inbreeding are common. We estimatethat in this
metapopulation, hybrid vigor amplifies the rate ofgene flow several
times more than would be predicted from thenominal migration rate.
This can affect the persistence of localpopulations and the entire
metapopulation.
1 Zoologisches Institut, Universität
Basel, Rheinsprung 9, 4051 Basel, Switzerland.
2 Tvärminne Zoological Station, SF-10900
Hanko, Finland.
3 Université de Fribourg,
Département de Biologie, Unité d'Écologie et
Évolution, Chemin du Musée 10, 1700 Fribourg, Switzerland.
4 Section of Integrative Biology, University of
Texas, Austin, TX 78712, USA.
5 Division of
Population Biology, Department of Ecology and Systematics, University
of Helsinki, Post Office Box 17 (Arkadiankatu 7), SF-00014 University
of Helsinki, Finland.
*
These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail:
dieter.ebert{at}unifr.ch
