This project will investigate genetic factors that have enabled the non-native algal species, starry stonewort, to establish and invade northern lakes in the United States. Aquatic invasive species have serious impacts on human and natural communities, and are very expensive to manage. Starry stonewort is considered rare in its native range of Europe and Asia, but has spread prolifically and become invasive since it was discovered in North America in the 1970s. The researchers will compare whole genomic data for algal specimens collected from both the native and non-native range and at different time periods to identify genes responsible for the rapid adaptation of this species to novel habitats in the United States. Results of this work will help in the development of tools and strategies for managing harmful invasive species. The project will involve mentoring of undergraduates, including of individuals from groups that are underrepresented in the sciences. In addition, the project will develop an algae diversity curriculum for high school and other K-12 students in New York City. <br/><br/>Genomes and genes of Nitellopsis obtusa will be surveyed to test the hypothesis that allele frequency shifts in this species are associated with rapid adaptation to novel chemical and nutrient regimes and novel climatic conditions of the invasive range. Genetic data will be collected from both fresh material and natural history collections, in the form of dried herbarium specimens, from the native and invasive ranges, at time points early and late in the invasion. This spatial and temporal sampling will allow allele frequency shifts to be tracked through time, to determine if significant changes have occurred in the introduced range. The nuclear genome of N. obtusa from native and invasive individuals will be sequenced to test gene content and organization relative to other green algae and land plants. A total of 48 candidate genes, representing an array of key functions, will be sequenced from the temporally stratified native and invasive samples. Results will lay the groundwork for future genotype-to-phenotype studies in this species and phylogenetic and genomic analyses of green algae.