2014 FMNH REU: LUIS ALLENDE (sophomore, Northestern Illinois University)
Advisor: Dr. Thorsten Lumbsch (Curator and Associate Director of the Integrative Research Center, S&E)
Symposium Presentation Title: What's in a name? That's what we call a species - addressing species delimitation in script lichens
Symposium Presentation Abstract: Script lichens(Graphis scripta) consists of a morphologically diverse group of licheinized fungi, that was until recently considered to represent a single species. Due to an absence of secondary chemistry and lack of taxonomically useful characteristics, species delimitation within this complex has been difficult and thus far has been based entirely on overall appearance of the apothecium. In this study we used molecular sequence data along with measured characters of the apothecia(length, width and thallus margin), to reconstruct a phylogeny in order to identify distinct lineages. We generated sequences for four genetic markers in 65 North American and European specimens which were added to previously collected data from 54 additional samples. We then performed a phylogenetic analysis using the method of maximum likelihood. Eight distinct lineages were then distinguished using the general mixed Yule coalescent model (GMYC). These genetically distinct lineages however did not correspond to morphological species recently described within the complex. It was also not possible to describe these clades based on differences in measured characteristics. Future studies will require the identification of additional taxonomically useful characters before species within this complex can be formally recognized.
Original Project Title: What’s in a name? That’s what we call a species – addressing species delimitation in lichenized fungi
Original Project Description: One of the most successful group of fungi forms stable symbiotic associations with algae and/or cyanobacteria, so-called lichens. These fungi are called lichenized fungi and the traditional delimitation of species within this group of organisms was based mainly on morphology and secondary chemistry. Species were believed to have very wide distributions, often including different continents. However, DNA sequence data suggest that these concepts vastly underestimated the true diversity of lichenized fungi. Recent studies suggest that many distinct lineages are hidden under common species names. In a project focusing on species delimitation in Parmeliaceae and related clades, this study will address species delimitation in lichens in a phylogenetic context. DNA sequence data of different genes will be used to address the delimitation of species. The lichenized fungi selected for this study belong to the genus Oropogon in the family Parmeliaceae (Lecanorales) and will mainly include specimens from East Asia. Previous studies of this genus in the Neotropics revealed cryptic diversity and in this extension, the question will be addressed whether cryptic species can be discovered in East Asia as well.
Research methods and techniques: REU participants in this project will receive training in molecular and organismal research methods. They will learn how important a combination of both methods is for an understanding of the evolution of the diversity of life. The training will include introduction to the literature, handling of herbarium specimens. Chemical examination will include chromatographic methods, such as HPTLC and HPLC. Molecular methods will include DNA isolation, PCR and subsequent direct sequencing of certain gene regions. Subsequently, the analysis of DNA sequence data will be performed.