Genetic divergence and evolution of reproductive isolation in Eastern Mediterranean water frogs

• Applicant: Dr. Jörg Plötner
• Subject Area: Evolution and Systematics of Plants and Fungi
• Term: from 2002 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5363295

Water frogs (genus Rana) that occur around the eastern end of the Mediterranean Sea provide an opportunity to study the early stages of speciation. Populations living on Mediterranean islands have been isolated from mainland populations for between 12,000 and 5 million years. These populations may be either closely or only distantly related. Some of the distinct genetic stocks may hybridize. Studying this frog diversity with molecular and behavioral tools will inform us about rates and processes of speciation. Population pairs that differ in isolation time and history of hybridization have been selected. For each pair we will ask: 1) How much do the two populations differ genetically? 2) Can they hybridize successfully with each other? and 3) Does (or would) behavior help them avoid hybridization? To assess genetic divergence, we will use five molecular markers: sequences from coding and noncoding regions of mitochondrial DNA, microsatellites, internal transcribed spacer sequences, and allozymes. We will measure postzygotic reproductive isolation by viability and fertility in F1 progeny and in backcross progeny of crossing experiments, and by cytogenetic analysis of their gametogeneses. The amount of prezygotic isolation will be measured in experiments in which females choose between advertisement calls of same-group and different-group males. The relations of the three measures of divergence to each other and to the population history of the members of each pair will be determined on a comparative basis. Together, these data will provide insights useful to all evolutionary biologists.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1127: Radiations - Origins of Biological Diversity