Open Access Highly Accessed Research article

Evidence that pairing with genetically similar mates is maladaptive in a monogamous bird

Hervé Mulard1236*, Etienne Danchin13, Sandra L Talbot4, Andrew M Ramey4, Scott A Hatch4, Joël F White123, Fabrice Helfenstein5 and Richard H Wagner2

Author Affiliations

1 Laboratoire Fonctionnement et Évolution des Système Écologiques, CNRS-UMR 7103, Ecology Institute, Université Pierre et Marie Curie-Paris 6, 7 Quai St Bernard, 75005 Paris, France

2 Konrad Lorenz Institute for Ethology, Austrian Academy of Sciences, Savoyenstrasse 1a, A-1160 Vienna, Austria

3 Laboratoire Évolution et Diversité Biologique, UMR 5174, Université Paul Sabatier, 118 Route de Narbonne, 31962 Toulouse Cedex 9, France

4 U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska, 99508, USA

5 Evolutionary Ecology Group, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland

6 Laboratoire d'Écologie et de Neuro-Éthologie Sensorielles, Université Jean Monnet, 23 Rue Paul Michelon, 42023 Saint-Étienne Cedex 03, France

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BMC Evolutionary Biology 2009, 9:147  doi:10.1186/1471-2148-9-147

Published: 30 June 2009



Evidence of multiple genetic criteria of mate choice is accumulating in numerous taxa. In many species, females have been shown to pair with genetically dissimilar mates or with extra-pair partners that are more genetically compatible than their social mates, thereby increasing their offsprings' heterozygosity which often correlates with offspring fitness. While most studies have focused on genetically promiscuous species, few studies have addressed genetically monogamous species, in which mate choice tends to be mutual.


Here, we used microsatellite markers to assess individual global heterozygosity and genetic similarity of pairs in a socially and genetically monogamous seabird, the black-legged kittiwake Rissa tridactyla. We found that pairs were more genetically dissimilar than expected by chance. We also identified fitness costs of breeding with genetically similar partners: (i) genetic similarity of pairs was negatively correlated with the number of chicks hatched, and (ii) offspring heterozygosity was positively correlated with growth rate and survival.


These findings provide evidence that breeders in a genetically monogamous species may avoid the fitness costs of reproducing with a genetically similar mate. In such species that lack the opportunity to obtain extra-pair fertilizations, mate choice may therefore be under high selective pressure.