Sex and differentiation: population genetic divergence and sexual dimorphism in Mexican goodeid fish

Genetic differentiation arises due to the interaction between natural and sexual selection, migration and genetic drift. A potential role of sexual selection in speciation has received much interest, although comparative studies are inconsistent in finding supporting evidence. A poorly tested predic...

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Bibliographic Details
Published in:Journal of evolutionary biology 2007-09, Vol.20 (5), p.2048-2055
Main Authors: RITCHIE, M. G., HAMILL, R. M., GRAVES, J. A., MAGURRAN, A. E., WEBB, S. A., MACÍAS GARCIA, C.
Format: Article
Language:English
Subjects:
Animal Migration
Animal reproduction
Animals
Cyprinodontiformes - anatomy & histology
Cyprinodontiformes - genetics
Cyprinodontiformes - physiology
Evolutionary biology
Female
Fish
Freshwater
Gene Flow
genetic differentiation
Genetic diversity
Genetic Speciation
Genetic Variation
Goodeinae
Male
Mating Preference, Animal
Microsatellite Repeats
phylogeography
Sex Characteristics
sexual selection
speciation
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Summary:Genetic differentiation arises due to the interaction between natural and sexual selection, migration and genetic drift. A potential role of sexual selection in speciation has received much interest, although comparative studies are inconsistent in finding supporting evidence. A poorly tested prediction is that species subject to a higher intensity of sexual selection should show greater genetic differentiation amongst populations because females from these populations should be more choosy in mate choice. The Goodeinae is a group of endemic Mexican fishes in which female choice has driven some species to be morphologically sexually dimorphic, whereas others are relatively monomorphic. Here, we measured population divergence, using microsatellite loci, within four goodeid species which show contrasting levels of sexual dimorphism. We found higher levels of differentiation between populations of the more dimorphic species, implying less gene flow between populations. We also found evidence of higher levels of genetic differences between the sexes within populations of the dimorphic species, consistent with greater dispersal in males. Adjusted for geographic distance, the mean FST for the dimorphic species is 0.25 compared with 0.16 for the less dimorphic species. We conclude that population differentiation is accelerated in more sexually dimorphic species, and that comparative phylogeography may provide a more powerful approach to detecting processes, such as an influence of sexual selection on differentiation, than broad‐scale comparative studies.
ISSN:1010-061X
1420-9101
DOI:10.1111/j.1420-9101.2007.01357.x