Aponte 9629662 This research is aimed at characterization of selected species of the broadly distributed, species rich and pharmaceutically important red algal genus Laurencia. This study also is aimed at elucidation of phylogenetic relationships among species of Laurencia by molecular analyses and assessment of the distribution of Laurencia species by comparing molecular data obtained from specimens assigned to the same taxa from various geographical regions. Species characterizations will focus on Caribbean species and on species with cosmopolitan or pantropical distributions. The study will also address the phylogenetic relationships between members of the genus Laurencia, its closely related genus Osmundea and their mutual parasite Janczewsia. Laurencia and Osmundea are ecologically important genera that include numerous species whose identification is extremely difficult due to morphological plasticity. The proposed study will provide insight to the relevance of the morphological characters used to distinguish species in this group of algae as well as help to clarify the validity of morphological/reproductive characters used to segregate genera and subgenera among Laurencieae. Inclusion of Janczewsia as a common parasite of both genera will provide possible insights into the evolution of algal parasite-host relationships, and will be assessed by a combined approach of comparative morphology and molecular studies. Molecular characterizations of species and phylogenetic relationships at the level of genus, subgenus and species will be inferred from the analysis of nucleotide sequences from specific portions of the genome, i.e. nuclear and chloroplast genes. Molecular data will be analyzed by parsimony methods and phylogenetic trees will be generated.
