Molecular Systematics of a Rapidly Evolving Species Flock: The Mbuna (Cichlidae) of Lake Malawi

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9707532 Kornfield Irv Kornfield of the University of Maine will employ hypervariable microsatellite markers to study the systematics and phylogeny of the mbuna , a large group of cichlid fishes of Lake Malawi, East Africa, that have obligate ties to shallow, rocky habitats.. Mbuna represent a highly speciose assemblage known for rapid and extensive diversification over a short periods of time. Mbuna thus represent an ideal model system in which to examine processes (e.g., habitat fragmentation, trophic and spatial niche shifts, interspecific agonistic interaction, and sexual selection) that are associated with speciation and adaptive radiation. Kornfield will use microsatellite markers to construct a hypothesis of relationships among major lineages within the extremely large and complex mbuna genus Pseudotopheus. The molecular phylogeny will then be compared to one based primarily on morphological and behavioral traits. Kornfield also will examine characters found in the morphology and distribution of scales. This aspect of the project will be in collaboration with E. Leppitsch of the Austrian Science Foundation. A second part of the project will be to evaluate the hypothesis that allopatric populations of mbuna that display reproductive coloration exhibit the disjunct patterns of distribution as a consequence of vicariance. An alternate hypothesis, that the similarities in reproductive coloration stem from parallelism or convergence, also will be evaluated. Resolution of phylogenetic relationships within the mbuna will provide fundamental insights into the phenomena of sexual selection and behaviorally-mediated reproductive isolation. The project involves significant collaboration with a scientist from Malawi, and is co-funded by the U.S.-Africa Program in the Division of International Programs at the NSF.