ALBERT

Description:    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 species Tropheus 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 ( h 2 ) in situ from a sample of wild caught fish, and (2) estimation of h 2 from 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 of h 2 were 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 species Tropheus 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 fish Tropheus moorii . Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0785-2 Authors Martin Koch, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Alastair J. Wilson, Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT UK Michaela Kerschbaumer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Thomas Wiedl, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Christian Sturmbauer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158