African Cichlid Fishes: Model Systems for Evolutionary Biology

Abstract

▪ Abstract Cichlid fishes (Perciformes: Teleostei) found in the lakes of Africa have served as model systems for the study of evolution. The enormous number of species (1000 in Lake Malawi alone), the great diversity of trophic adaptations and behaviors, and the extreme rapidity of their divergence (<50,000 y for some faunas) single out these organisms as examples of evolution in progress. Because these fishes are confined to discrete lacustrine environments and their origination is bounded by geological features, these groups provide models with which to study evolution. We review theoretical studies and empirical research on the cichlid faunas of Africa to provide a synthetic overview of current knowledge of the evolutionary processes at work in this group. This view provides the critical information needed to formulate and test hypotheses that may permit discrimination among the diverse theories and models that have been advanced to explain the evolution of these fishes.

On the origin of Lake Malawi cichlid species: A population genetic analysis of divergence

“…The difficulty has generally been described as a consequence of very recent divergence (6,31,32). However, in the absence of phylogenetic assessments, it is difficult to know to what degree recent speciation is the cause of shared variation and the lack of phylogenetic resolution.…”

Molecular Characterization of Two Endothelin Pathways in East African Cichlid Fishes

“…No other vertebrate family consists of such a great number of species (at least 3,000 species worldwide), such a degree of phenotypic diversity and such a rapid diversification rate. Above all, the species flocks of cichlids in the East African Great Lakes show the greatest variation in morphology, coloration, ecology, behavior, and reproductive biology (Barlow 2000;Coulter 1991;Fryer and Iles 1972;Keenleyside 1991;Kocher 2004;Kornfield and Smith 2000;Salzburger 2009;Seehausen 2006). Furthermore, the cichlids' occurrence in various geographic regions (Africa, India, Sri Lanka, and Central and South America) and the independent (and repeated) colonization of multiple African lakes (e.g., lakes Malawi, Tanganyika, and Victoria) form the basis for some outstanding cases of parallel evolution within and between lakes and regions (Duftner et al 2007;Elmer et al 2010;Kocher et al 1993).…”

Evolution in closely adjacent plant populations X: long-term persistence of prereproductive isolation at a mine boundary

“…Empirical evidence that sympatric speciation can occur has lagged behind these theoretical studies, but has gradually accumulated through experimental work (Rice and Hostert, 1993) and detailed genetic analysis of field populations (Hawthorne and Via, 2001). It has been strongly suggested, if not proved unequivocally in every particular instance, that under certain ecological and genetic conditions closely related species have probably speciated in sympatry, especially in phytophagous insects (Berlocher and Feder, 2002), parasites (McCoy, 2003), and the cichlid fishes (Kornfield and Smith, 2000).…”