Phylogeography of Haplochromine Fish in the Lake Victoria Region

again somewhere and celebrate our traditional barbecue on the roof !!! Johannes set foot on the shores of the Great East African Lakes. Luckily, Darwin stumbled over some remote Islands in the Pacific Ocean instead and found some finches there, and later wrote his famous books. I think we are very lucky that we have something like an Evolutionary Theory today. For if Darwin had seen the splendid diversity of cichlid fish in these lakes, things would have become too complicated. Then he would no longer have believed his own wicked smart theory and would have denied everything on the spot… However, Darwin´s ideas are still around and the Great East African Lakes keep on attracting evolutionary biologists. 2.1 Overview Cichlid fish (Family Cichlidae, Order Perciformes) are widely distributed in the rivers and lakes of Africa, South America, India, Sri Lanka and Madagascar, but they reach their maximum diversity in the East African Great Lakes (Tanganyika, Malawi, Victoria) and surrounding rivers. This family of fish is one of the most species-rich families of vertebrates with at least 3,000 and perhaps as many as 5,000 species (Kullander, 1998). The three East African Great Lakes harbour surprisingly large endemic cichlid species flocks. An endemic species flock is a closely related group of species, which exclusively occur in this lake. The extent of endemism and the number of species seem to depend on size, depth and age of the lakes. As the radiations of the species flocks in different lakes can thus be compared to each other, these ecosystems are seen as excellent models Introduction 3 for the study of adaptive radiations. 2.2 Origin of the Lake Victoria cichlids From morphological data it was suggested that the species flock of 300 to 500 cichlid species inhabiting Lake Victoria arose in situ, by intralacustrine speciation, from a single founder lineage With the development of molecular techniques, this hypothesis was strongly supported by molecular data. In 1990, Meyer et al. suggested a monophyletic origin of the LV species flock based on mitochondrial DNA sequences (D-Loop and Cyt.b). Later it could be shown that both the Lake Victoria and the Lake Malawi species flocks probably originated from a mouthbrooder of the tribe both the Lake Malawi and the Lake Victoria cichlids and their common ancestor are referred to as haplochromines and this is also the reason why the haplochromines are genetically so similar within these two …