Speciation processes in two co-distributed freshwater turtle complexes in a hotspot of genetic diversity (Emys orbicularis complex; Mauremys caspica, M. rivulata)

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Processes underlying allopatric speciation will be studied in turtles, a group of animals capable of extensive hybridisation, even among distantly related taxa. To gain deeper insights in the question how speciation occurs despite this capability to hybridize, we plan to analyze gene flow in two species complexes with a different degree of reproductive isolation, with similar distribution ranges and similar ecological traits using polymorphic microsatellites and mtDNA sequence variation to address the following questions: (1) Do the two co-distributed species complexes show the same general patterns of differentiation, introgression, and gene flow? (2) What is the impact of isolation-by-distance and geographic barriers for the formation of genetic discontinuities? (3) How do the genetic differentiation and introgression patterns compare with other taxa? Are there any peculiarities in chelonians that might help to understand their extreme capability to hybridize? (4) Do mitochondrial and nuclear genomic patterns agree or conflict in each of the two model systems? (5) Are their phylogeographic patterns congruent or conflicting, despite shared habitats and identical or at least very similar selective forces?