Project groups

L-1.9 | PHYLOGEOGRAPHY AND SPECIATION OF LICHENS FROM THE CETRARIA ACULEATA COMPLEX IN WESTERN EURASIA AND EAST AFRICA

Project leader:
Dr. Christian Printzen

In spite of their importance, both for ecosystems and as model organisms for ecologists, the diversity, distribution and evolution of lichens is still poorly known. One problem in detecting and describing the diversity of lichens has always been the variability of morphological characters. Recently, DNA sequence data has become an important additional tool to study the delimitation of lichen species. Population level studies have demonstrated considerable infraspecific genetic variability that some authors ascribed to the presence of cryptic lichen species. If such analyses are based on one or a few genetic markers, there is a great danger that infraspecific lineages are misinterpreted as separate species with profound implications for the conservation of lichens and their use as ecological indicators. Using the Cetraria aculeata group as a model case, including the polar-alpine C. muricata, C. nigricans, C. odontella as well as C. steppae and C. crespoae from the Mediterranean region, the project addresses the following questions: (1) Where can we draw borders between species within the complex? (2)  To what extent are African and western Eurasian populations from the C. aculeata complex genetically isolated? Are the gene pools of C. crespoae  and C. steppae more isolated from the rest of the populations or does geographic isolation prevail? (3) Are Afroalpine populations of C. aculeata derived from or ancestral to Eurasian ones? (4) Do patterns of differentiation between Afroalpine and western Eurasian mycobiont populations coincide with differences in photobiont use? We will also compare methods of multilocus species tree reconstruction, estimation of gene flow (based on microsatellite markers) and simple DNA barcoding approaches to assess their usefulness for species delimitation in lichens. 

Team

Tetiana Lutsak, Ph.D. student