title: Additive genetic variance of quantitative traits in natural and pond-bred populations of the Lake Tanganyika cichlidTropheus moorii.
abstract: Quantitative genetic studies in natural populations are of growing interest to speciation research since divergence is often believed to arise through micro-evolutionary change, caused by natural selection on functional morphological traits. The species flock of cichlid fishes in Africa's oldest lake, Lake Tanganyika, offers a rare opportunity to study this process. Using the cichlid speciesTropheus moorii, we assessed the potential for microevolution in a set of morphological traits by estimating their quantitative genetic basis of variation. Two approaches were employed: (1) estimation of trait heritabilities (h2) in situ from a sample of wild caught fish, and (2) estimation ofh2from first generation offspring produced in a semi-natural breeding experiment. In both cases, microsatellite data were used to infer pedigree structure among the sampled individuals and estimates ofh2were made using an animal model approach. Although power was limited by the pedigree structures estimated (particularly in the wild caught sample), we nonetheless demonstrate the presence of significant additive genetic variance for aspects of morphology that, in the cichlid speciesTropheus moorii, are expected to be functionally and ecologically important, and therefore likely targets of natural selection. We hypothesize that traits showing significant additive genetic variance, such as the mouth position have most likely played a key role in the adaptive evolution of the cichlid fishTropheus moorii.
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Koch
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT UK.
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Wilson
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Michaela
authors.initials: M
authors.lastname: Kerschbaumer
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wiedl
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Sturmbauer
keywords: Animal model; Evolutionary potential; Heritability; Lake Tanganyika; Tropheus moorii; VA