Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Microevolutionary processes and macroevolutionary patterns of diversification in cichlid fishes: lessons from extremely young species flocks

Axel Meyer

University of Konstanz, Germany

Abstract

The exceptionally diverse species flocks of cichlid fishes in the East African Great Lakes are prominent examples for replicate adaptive radiations and explosive speciation. The hundreds of closely related cichlid species often differ greatly in ecologically relevant traits such as mouth morphology and dentition. These patterns of convergent evolution across lakes will be discussed in light of the patterns of ecological diversification of these species flocks. Cichlids also display a great diversity in coloration and pigmentation patterns indicating the importance of sexual selection in this group. We have studied the molecular evolution of several candidate color genes in East African cichlid species and find evidence for adaptive sequence evolution in some of them. For example, we can show that /csf1ra/ evolved under positive selection in the ancestor of the haplochromines (the most species-rich group of cichlids), in which this gene is expressed in the egg-dummies on male anal fins. These egg-spots mimic real eggs and play a crucial role in the breeding cycle of these mouth-brooding fish by guiding the female’s mouth close to the male’s genital opening. This facilitates the fertilization of the eggs within the female’s mouth. The comparative analysis of color genes also provides novel insights into the general patterns of evolution in East African cichlids. The mechanisms of speciation were studied in Nicaraguan crater lakes in detail. In these ecological settings species were found to have arisen in record speed and often through sympatric speciation.

Axel Meyer

University of Konstanz, Germany

Biography

Axel Meyer studied biology at the universities of Marburg, and Kiel in Germany and moved to the US in 1982 where he studied in Miami, Berkeley und Harvard. He received his Ph.D. (1988) in zoology from the University of California in Berkeley and worked as a postdoc (1988-90) at Berkeley’s biochemistry department in the lab of Allan C. Wilson. In 1990 he moved to the Department of Ecology and Evolution at Stony Brook where he was an Assistant (1990-93) an then Associate Professor (1993-97). Since 1997 he is Professor of Zoology and Evolutionary Biology at the Biology Department at the University of Konstanz in Germany. He received several honors including an Alfred P. Sloan Foundation Postdoctoral Fellowship, the Young Investigator Award of the American Society of Naturalists, a Simon Guggenheim Memorial Fellowship, a Miller Research Professorship from Berkeley, the Akademiepreis of the Berlin-Brandenburgischen Akademie der Wissenschaften, the EMBO Communications Award and the Carus Medal of the Leopoldina, the National Academy of Sciences of Germany. He is a member of the European Academy of Sciences, the Leopoldina and the Berlin-Brandenburgische Akademie der Wissenschaften. He was a guest professor at Stanford University, Berkeley and the University of Ottawa. He published more than 300 articles including in some in Nature and Science. He has written many articles for the popular press and writes weekly a newspaper column for the German newspaper Handelsblatt.