Dr. Fabian HerderSektion Ichthyologie, Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, 53113 Bonnhttp://www.zfmk.de/web/ZFMK_Mitarbeiter/HerderFabian |
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Adaptation, speciation and gene flow: patterns of radiation in Sulawesi`s sailfin silverside fish |
| Speciation, the processes splitting a species into two or more, is a topic of major interest in evolutionary biology. Different mechanisms may drive population divergence and finally speciation, including morphological adaptation to resource use and non-random mating. Theoretical and empirical evidence suggest that processes generating biological diversity are not restricted to strict allopatric scenarios, which have been favoured for decades. In contrast, adaptive speciation under sympatric or parapatric conditions seems to be a plausible alternative. The radiation of sailfin silversides (Atheriniformes: Telmatherinidae), small freshwater fish endemic to ancient lakes in Central Sulawesi (Indonesia), is a model system allowing to test hypotheses regarding early phases of speciation and species-flock formation under different geographic settings. Present results suggest ongoing gene flow among different clades of Telmatherinidae, support the idea that this radiation is adaptive, and indicate that “roundfin” sailfin silversides of extraordinary deep Lake Matano represent an early stage of sympatric speciation. Interestingly, restrictions in gene flow are present among three ecologically distinct “roundfin” morphospecies, but not among conspicuously distinct male colour morphs. Explorative AFLP-based genome scans suggest that divergent selection affects only 1.3-4.2% of the analyzed loci, which is consistent with an early stage of speciation. In summary, the sailfin silversides radiation provides examples for adaptive radiation, hybridization and incipient sympatric speciation within one single, compact model system. |
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Ort |
| 03.12.2008 15:00 Uhr Großer Hörsaal |
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