CORDIS

Phylogeography is an integrative scientific field that uses genetic information to study the geographic distribution of genealogical lineages. Its major goal is to infer the evolutionary and ecological processes that have left a genetic imprint on organisms. For these reasons, phylogeography provides a historical perspective, vital to biogeography, speciation, biodiversity research, taxonomy and conservation biology. Phylogeography is in the early stages of embracing newly developed massively-parallel methods of DNA sequencing (Next Generation Sequencing - NGS), to generate the data needed for acquiring robust phylogenies and phylogeographical histories. Comparing phylogeographical patterns among multiple co-distributed species can elucidate the complex relationship between landscape and biota through time. The main aim of the project CO-PHY-MED is to investigate the mechanisms and processes that drive divergence and speciation, and shape the biogeographical history of organisms, by using the Mediterranean as an empirical example and squamate reptiles (lizards and snakes) as the model organisms to conduct a large-scale multi-species comparative phylogeographic analysis.

Model region
The Mediterranean Basin is an area where biotic elements of the surrounding biogeographical regions of Europe, Asia and Africa converge and is recognized as a Global Biodiversity Hotspot. The Aegean region (Greece, Turkey) and the strait of Gibraltar (Spain, Northwest Africa), specifically, have become natural laboratories for phylogeographic investigations. Several factors are responsible for the rich biodiversity in these regions: (1) Position and complex geological history: The Aegean lies between Asia, Europe and Africa (through the Middle East), while the strait of Gibraltar, that now acts as a barrier to species’ dispersal, has served as a corridor between Europe and Africa. This resulted in an interesting mixture of faunal elements of different origin for both regions. (2) Geomorphology and islands: Islands provide important models for understanding drivers of diversification and the Mediterranean includes almost 12,000 islands, the majority of which are located in the Aegean Sea. (3) Refugia: The Balkan and Iberian peninsulas have acted as refugia during the climatic changes of the past 2-3 million years. (4) Human activity has been recorded here for more than 10,000 years and has influenced the distribution of many organisms.

Model organisms
More than 350 terrestrial reptile-species live in the Mediterranean region: most of them are squamates, about half of them are endemic, and the largest number of species in Europe is found in Spain and Greece. Reptiles display a great diversity in their biology and offer outstanding models in ecology and evolution, mostly because of (1) their temperature-dependence that renders them particularly sensitive to climatic changes and (2) their diversity of dispersal and colonisation capacities, and ability to overcome barriers. Barriers are essential for speciation and biogeography, by isolating populations.

The major research objectives of CO-PHY-MED are:
(1) Collect genomic data for co-distributed species of squamate reptiles in the Aegean and Gibraltar using NGS methodologies and applying two approaches: sequence capture (seq-cap) and double-digest restriction-site associated DNA sequencing (ddRAD).
(2) Reconstruct the phylogenetic relationships among and within the studied species for the two areas.
(3) Infer across-barrier diversification among co-distributed species and test alternative hypotheses to explain patterns.
(4) Identify the major barriers that have influenced the formation and evolution of biodiversity.

The major training objectives of CO-PHY-MED are:
(1) Experimental design in phylogenomics.
(2) Preparing biological samples for genomic approaches.
(3) Handing genomic data and performing phylogenomic analyses.