Introgressive hybridization between color morphs in a population of cichlid fishes twelve years after human-induced secondary admixis

Egger, Bernd and Sefc, Kristina M. and Makasa, Lawrence and Sturmbauer, Christian and Salzburger, Walter. (2012) Introgressive hybridization between color morphs in a population of cichlid fishes twelve years after human-induced secondary admixis. The journal of heredity, Vol. 103, H. 4. pp. 515-522.

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Official URL: http://edoc.unibas.ch/dok/A6070374

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In the extremely species-rich haplochromine cichlid fishes of the East African Great Lakes, prezygotic isolation between closely related species is often maintained by color-assortative mating. In 1998, local fisherman working for the ornamental fish trade released different color morphs of the cichlid genus Tropheus into a small harbor basin in the southern part of Lake Tanganyika. This artificial amalgamation of color morphs provides a unique possibility to study mating patterns in cichlids in a natural environment over time. In a precursor study, we analyzed genotypes and phenotypes of almost 500 individuals sampled between 1999 and 2001 and uncovered a marked degree of color-assortative mating, which depended on the level of color pattern dissimilarity between morphs. Twelve years after introduction of nonindigenous morphs, we again sampled Tropheus individuals from the harbor basin and an adjacent, originally pure population and analyzed phenotypes (coloration) and genotypes (mitochondrial control region and 9 microsatellite loci) to assess the current status of the admixed population. Principal component analyses of color score data and population assignment tests demonstrate an increasing level of introgressive hybridization between morphs but also some ongoing color-assortative mating within morphs. The observed mating pattern might have been influenced by fluctuating environmental conditions such as periodic algal blooms or increased sedimentation causing turbid conditions in an otherwise clear lake.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Integrative Biologie > Evolutionary Biology (Salzburger)
UniBasel Contributors:Salzburger, Walter
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Genetic Assoc.
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:21 Jun 2013 12:29
Deposited On:21 Jun 2013 12:27

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