Studying adaptive radiation at the molecular level: a case study in the Macaronesian Crassulaceae-Sempervivoideae

• Applicant: Dr. Mike Thiv
• Subject Area: Evolution and Systematics of Plants and Fungi
• Term: from 2004 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5422951

Many studies have attempted to identify genes involved in lineage diversification. The aim of this project is to test the impact of regulatory versus structural genes in the process of speciation in the Macaronesian Sempervivoideae. This plant group is a classic example of an island radiation as inferred from its diverse morphology and ecology. Substitution patterns of genes affecting the phenotype, e.g., regulatory genes (Apetala1, Apetala3) and structural genes (Chalcone synthase, PEP carboxylase, and g-T onoplast intrinsic protein), will be analyzed. Increased mutation rates of regulatory and/or structural genes are expected, when comparing the adaptively radiated island clade to its non-radiated mainland sistergroup. This would indicate positive selection acting upon these genes. Analyzing the selected genes that are potentially involved in either the evolution of floral morphological or physiological key characters enables us to distinguish between different forces driving speciation. The comparison of evolutionary rates between these genes presumably affecting reproductive isolation and physiological adaptation will yield an indirect measurement of the degree to which these forces are linked to species diversification in Macaronesian Sempervivoideae. Furthermore, correlations between speciation and substitution rates will be sought. Such an interdisciplinary approach can contribute to a better understanding of the processes behind evolutionary diversification and speciation.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1127: Radiations - Origins of Biological Diversity
• Participating Person: Professor Dr. Marcus Koch