MSc - Genetic analysis of the contact zones of Lizards
|Advisors:||Octávio S. Paulo; Andreia Miraldo|
Lacerta lepida is a lizard species that belongs to a small group of lizards that exist in North Africa and Western Europe.
Lacerta lepida is the only species from the group that exists in Europe, being distributed mainly throughout the Iberian Peninsula, southern France and northwestern Italy. A recent phylogeographic study (Miraldo et al., in press) using mitochondrial and nuclear genealogies, revealed that Lacerta lepida, like other species in the region, has endured repeated processes of fragmentation that have promoted the diversification of six genetically and geographically distinct lineages. Diversification within the species was highly influenced by the Pleistocene climatic oscillations, but earlier geologic events (during the Miocene) have also played an important role. Detailed phylogeographic analysis has revealed areas of secondary contact between the divergent lineages, formed mainly as a result of demographic range expansions after the last ice-age. The dynamics of gene flow was assessed in a contact zone between the most divergent mitochondrial lineages within the species (lineage L and N) in south-eastern Spain. The microsatellite analysis of this contact zone revealed very restricted gene flow amongst the lineages and it was postulated that the lineages are on independent evolutionary paths and therefore should be considered as two different species. For future work it would be interesting to assess the mechanisms that are driving speciation in these lizards by making comparing detailed genetic analysis of secondary contact zones which differ in the amount of mitochondrial genetic divergence between the lineages in contact. The objective of the project is therefore to analyze with microsatellites the pattern of genetic variation in 3 transects, across three different contact zones, and comparing them in function of the mtDNA divergence, and with the one already analyzed (Miraldo et al., in press).